Thursday 29 December 2011

Lines in Grade VII

Hello friends in this article we are going to discuss important geometrical topic that you study in grade VII. A line can be defined as a continuous extent of length, straight or curved, without breadth or thickness; The notion of the line was very first introduced by ancient mathematicians to represent straight objects and things with negligible width and depth. in more mathematical term the same can be defined as a geometrical object that is straight, infinitely long and infinitely thin. There are different types of lines like straight line, parallel line, perpendicular lines, intersecting lines, many more. Properties mean any qualities, features that are embedded in line.

Let’s focus on the properties of parallel lines. Parallel lines are those lines which move right next to each other and they move infinitely long but never cut each other. Properties of same said that, the two lines lie in the same plane, and do not intersect or cross each other. The properties of parallel line based on the Euclid’s parallel property means they can’t cut each other at any point. In other word the property says that lines are nothing with a pair of lines in a same plane which do not cut or meet each other. In this, we can introduce the other line called as transversal line that crosses a pair of parallel lines on a slant.

 

Let’s have an example of the properties of the parallel lines.    

Example 1:

Define the equation parallel to line 4q + 4p = 8 with the point (-6, 4).

Answer:

Given,

 4q + 4p = 8 and the point (-6, 4)

To detect the parallel line, we have to find the slope first.

For finding the slope, we need to change the given equation into slope intercept form.

4q + 4p = 8

Do addition of 4p on both sides of the equation,

4q + 4p = 8

- 4p = -4p

4q = -4p + 8

Divide by 4 on both sides,

q = (-p + 2)

The obtained equation is in the form, q= mp + b

So, the slope from the obtained equation m = -1

Generally, we know that the slope of parallel lines are equal i.e. m1 = m2

Here, m1 = -1

So, m2 = -1

The line equation is,

(q - q1) = m(p - p1)

(q - (4)) = -1 (p - (-6))

(q - (4)) = -(p + 6)

q - 4 = - x - 6

Subtract 4 on both sides,

q = -p - 2

Output: Thus, the pictures of parallel lines is given through the lines q= -p - 2, 4q + 4p = 8.

In this way we solve problems related to parallel lines. Geometry is very interesting mathematical part, that you can easily understand with help of bit practices. So do practice and score good marks and feel proud.

Wednesday 28 December 2011

Angles in Grade VII

Students, today I will make you aware with geometry of Grade VII. Before we move to any topic or any other things tell me what is geometry? Geometry is any well defined shape; each solid object has its own geometry that describes its shapes, properties, etc. Geometry is all about shapes, if you get familiar with shapes then you are the hero of geometry. as you study algebra from primary grades similarly you will also learn geometry from primary schools. As you grow up and grade changes complexity of topics also changes.

Today we are going to talk about Complementary and supplementary angles. First go through complementary angle. Two angles are called as complementary if the sum of their angles is equal to 900. If one angle is known, than its complementary angle can easily be determined by subtracting the measure of its angle from 900.   

For instance: What is the complementary angle of 47o
Solution: 90o  -  47o  =  43o

Whenever we have to determine the complementary angle and one is given minus it from 90 and the resultant angle is determined in this way.

Example 2: if we have two angles as 270 and 630, are they complementary angles or not.

Answer: we have two angles,

One is 27, and other is 63,

If we add both the angles then they will give result as: 27 + 63 = 90,

Hence it is a complementary angle, as sum of both the angles is equal to 90 which is the condition of complementary angle.  

 

Now, the other type of angle i.e. called as the supplementary angle, if the sum of two angles is equal to 180 then such kind of angles are named as Supplementary angles. When one angle is unknown to you and you have to determine the unknown one then you can easily calculate it by subtracting the given angle from 1800.

Let’s see how to calculate the unknown angle with help of example.

Determine the second supplementary angle when one is 143o
Answer: 180o  -  143o  =  37o

Now the other example of the same, calculate that the given angles form a supplementary angle or not?

 Suppose you have two angles, 1000 and 800,

You can easily say that both angles results, supplementary angle. Because when we add them they will give result as:

1000 + 800 = 1800

Thus, satisfying the condition of the supplementary angle.

Example: one angle is 240 and other is 580  tell whether it is complementary or supplementary angle.

Solution: Angle one = 240, second angle = 580,

first + second = 240 + 580,

                            = 820.

As on adding both angles we are getting only 82, so it is neither a complementary angle nor supplementary. Because for complementary angle it must be equal to 900 and for supplementary it must be 1800.
In the upcoming article we will talk about other topics of geometry and if you have any doubt than you can take my help easily. I am here to help you and to solve your mathematical problems. 

Sunday 25 December 2011

Multistep Problems in Grade VII

Algebra! Who invented this boring branch of mathematics. Many students usually ask this question. But my dear students I am here to take your pain and to make this boring subject an interesting one for you. Whenever you deal with any math problem try to understand the problem behind the concepts and relate it with the real life problems then surely friends you will understand the problem properly. Now, move towards the today’s topic that is multistep problems in grade VII. What do you understand by the term multistep problems? As the name says multistep, you easily understand its concept that multistep means multiple step and by multistep problems we mean that how to solve problems involving different steps.

In multistep problems, a problem is solved in different steps and each and every step is very important. If you solve any problem and if any of its step is wrong then you won’t get the final answer right. In such type of problems each and every step must be right otherwise the output will be wrong even a minute mistake can cause problem to your answer. so be careful whenever you solve these types of problems and check and all the steps properly and carefully. The multistep problems can be in any form like they can be in equation form or word problem form.

Let’s take an example and understand the problem properly.  

First take an example of equation which is solved in multistep.

Example: Solve the given equation for the variable q

20 = 3(2 q + 8) + 4

Answer:

-20 = 3 (2q + 8) + 4

Eliminate the parentheses,

-20 = 3 (2 q) + 3 (8) + 4

-20 = 6q + 24 + 4

-20 = 6q + 28

Subtract 28 on both sides of the equation

-20 - 28 = 6q + 28 – 28

-48 = 6q

Divide by 6 on both sides of the equation

-48/6 = 6q/6,

-8 = q

This is the final answer of the equation.

 

 

Now, here is an example of the same but the form of word problems.

Question: Allen earns a base salary of $94 per week with a commission of 14% of sales. if she had $100 in sales last week, then find her total pay.

Solution: as you all know the formula to calculate commission and total pay.

Commission = commission percentage x sales,

Total pay = base salary + commission.

First calculate the commission. For this we can use the first formula

Commission = commission percentage x sales,

= 14 % x 100

= 14 /100 x 100,

= 14.

so the commission is $14.

Now we can easily calculate the total pay, using second formula,

total pay = base salary + commission,

= 94 + 14,

= 108,

The total pay was $108.  

in this the simple way to solve multistep problems only take care that all the calculations and formula used are right or not, then you can easily solve all the different problems.

Friday 23 December 2011

Linear Equations VII Grade

Hello my dear students, today we will focus on few more topics of algebra that you study in class VII. As you all now algebra is an interesting subject if you study it with interest and one of the boring subject if things go out of your mind then it is one of the difficult subject. In this article we will talk about Linear/non-linear functions, equations, inequalities. What do you understand by linear function? A linear function can be defined as a polynomial function of single degree. In this we relate a dependent variable with an independent variable in a simple way. It is that mathematical equation in which there is no independent variable that is raised to power greater than one. We can define the simple linear function as a linear equation which is having a single independent variable (y = a + bx), which results in a straight line when we plot the same on the graph.  

Now, let’s switch gear towards the form of linear function. In order to define the linear function we need an equation of first degree. The general form of linear function of first degree is given as:

f= (x, y)/ y = mx + b

In this m and b are constants, x and y are the linear function. When we plot the graph of same it will give a straight line. There are three main forms or types in linear functions.

  1. Slope- intercept form: its general form is given as: y = mx + b,

 

2) Point slope for, its general form is given by m = (y –y1) / (x – x1)

3) General Form is given as: Ax + By  + C = 0.

Now, have a look on how to solve the linear functions. Solving the given function by altering its position and simplifying the equation to get Y is generally known as solving linear equations. The solution of these equations provides solutions of the corresponding practical problems. Here are few steps that you can use when you deal with the linear function in word problem form:

  1. Read the given problem properly and then note down what is given to us in problem and what other things are required.
  2. Denote the unknown quantities by literals like x, y, z, u, v, etc.
  3. Translate the statements of the problem step by step in mathematical form so that we can get what to do.
  4. After that, look for the quantities that are equal. And then make the equations corresponding to these equality relations.
  5. Use an appropriate method and solve the equation formed in step 4.
  6. It is the last step and in this you have to check the solution of the problem by substituting the value of the unknown found in step 5. Now, let’s have few examples of linear functions so that you can easily understand the concept and process of solving linear function problems.  

Example 1: Solve for a and b, where, b = a+ 13 and 2a ? b ? 10 = 0

Solution: in this we can easily put the value of the b as b = a + 13 in the equation

      2a ? b ? 10 = 0  

 2a ? (a + 13) ? 10 = 0,

a ? 23 = 0,

a = 23.

Now put the value of a  23 in 2a ? b ? 10 = ,

? y + 36 = 0,

? y = ? 36,

y = 36.

After linear function it’s the time to move towards the next topic that is called as the non- linear function. In simple terms we can define non-linear function as an equation whose graph is not linear and an equation with degree two or more than two. The general form of the same is given as:

f(x) = +….+ a1x1 + a0 where a0, a1 ..an are stables. In the non linear function an is defined as a primary co-efficient and an xn is principal term. The greatest degree of non-linear function is greater than two or similar to two. In non linear function, graph can be a curve, zig- zag line, or any even shape but it can’t be a straight line. The Non linear function can be defined in quadratic form, exponential form and logarithmic form.

Different types of non linear function deals with solving several types of polynomial function where as polynomial function is also called as non linear function.  We can solve the non linear function using substitution method or quadratic equation operations, etc. 

 

Non linear functions play an important role in algebra. Any of the function is not a linear function and can’t be a complete linear function by transforming the Y variable.  

Normally, there are three types of non linear function that we use in mathematics, they are given as:

  1. Exponential function
  2. Quadratic function
  3. Logarithmic function

This is the time to see few examples of the non linear functions.

Example 1: x² - x – 12 = 0, calculate the value for ‘x’ for the given non linear function.

Answer:

As you all know the given equation is in form of x2 – 4x +3x - 12 = 0, which resembles with the general form of quadratic equation.

Now, we can get the value for x from the primary term and 3 from secondary term.

x (x – 4) + 3(x - 4) = 0

Now combine the like term (x -4)

(x + 3) (x - 4) = 0

To get the value for x we can associate the factor to zero

a + 3 = 0 or a – 4 = 0

a = -3 or a = 4

a = 4

Thus, the factors a1 and a2 are -3, 4.

Example 2:

p² - 3p – 10 = 0, determine the value for p for the non linear function.

Answer:

Now, we can find the factor for the given quadratic equation

p2 – 5p +2p - 10 = 0

Now, get the value for x from the primary term and 3 from secondary term.

p(p – 5) + 2(p - 5) = 0

Now we can combine the similar term (p - 5)

(p + 2) (p - 5) = 0

To get the value for x we can associate the factor to zero

p + 2 = 0 or p – 5 = 0

p = -2 or p = 5

Thus, the factors p1 and p2 are -2, 5.

Example 3:

x² - 6x + 5 = 0, get  the value of x for the given non linear functions

Solution:

First we can learn the factors for the given quadratic equation

Sum of the roots (-6) = (-5) + (– 1)

Product of roots (5) = (-5) × (-1)

By combining these two roots we can obtain the factor form as,

x2 – 5x - x + 5 = 0

Now get the value for x from the primary term and 5 from secondary term.

x (x – 5) - 1(x - 5) = 0

Now we can combine the similar term (x - 5)

(x - 5) (x - 1) = 0

To get the value for x we can associate the factor to zero

x - 5 = 0 or x – 1 = 0

x = 5 or x = 1

Thus, the factors are x1 and x2 and the values are 5, 1.

Now, switch to other topics Equations and inequalities. You all are familiar with both these terms. Here, I will give a brief introduction of both the topics as you are reading the same from earlier classes.  Equations are those mathematical statements that are joined together with help of equal to symbol. There are many different types of equations like linear equations, quadratic equations, polynomial equations, and many other types of equations. There are several different types of methods that you can use to solve different types of equations like linear equations can be solved by simple motion of the variables and constants.

Inequalities can be defined as an expression which is defined using special symbols.  Mainly four different inequality symbols are used using which inequalities are defined like: greater than (>), greater than equal to (<), less than (>=), less than equal to (<=). Solving linear equalities is very simple and you can easily solve them. Solving linear equalities are very similar to solving a linear equation. Inequalities give infinite number of solutions and the answer is right only when the inequality is true.

In all the above mentioned topics for any problem you can take online help and solve all your problems.       

Tuesday 20 December 2011

Numeric Expressions in Grade VII

Mathematics is a wonderful language that deals with different types of numbers. Math is a broad subject that is divided in several different types of branches. In this section we are going to focus on the few important topics of algebra a pure branch of mathematics of grade VII. In this grade students usually study algebra 2. Algebra is nothing but it is simply the movement of the numbers, variables, and constants. If you love playing with numbers then definitely you we will love this subject. Now, come to the topic that is simplifying numerical expression.

Before we move to simplification of the numerical expression, let’s talk about the expression and simplification individually. Expression is a finite combination of the symbols that is well-defined and formed according to rules that depend upon the context. Symbols can designate numbers constant, variables, operators, functions, and other different types of mathematical symbols. These symbols includes punctuation, symbols of grouping, and other syntactic symbols. In algebra we generally deal with two different types of expression one is numeric and other is algebraic expression. An algebraic expression is that mathematical phrase that contains ordinary numbers, variables such as a, b ,x, y,.. and operators like add, subtract, multiply, and division. Let’s have a look on different types of algebraic expression.

a+ 2,

x- y,

6x,

c- 3/4d and other such type of expressions.

Now, the other type of expression that is called as the numeric expression, this means involving numbers and the term expression means “phrase”. In simple terms we can describe the same as: a mathematical phrase involving only numbers and one or more operational symbols.
Here are few examples of numerical expression,

5 + 20 – 7,

(1 + 3) – 7,

 (6 × 2) ÷ 20,

 4 ÷ (20 × 3),

7 × (42 + 3)

 

A numerical expression is the group of numerical or numeral values, which are separated by addition or subtraction. Numerical expression is simply the real number or all the positive values(1,2,3,4,5,6…) and negative values(-1,-2,-3,-4,-5,…) and zero. Order of process is one of the methods used to evaluate the numerical term in given expression.

Now, talk about simplification, the term simplification means reducing any expression to the least value for where we can divide the expression again. In other words we can say that simplification means solving the expression and removing all the complex or simple operators from the expression.  Simplification of numerical expression means removing all the possible operators from the expression and taking the same to the simplest from, which will not contain any type of operator. The different numerical expression will always contain the numeric values only; They never contain the variables or any alphabetic value. While on the other side algebraic expressions contains both the numeric as well as variables with different type of operators.

Simplification of Numeric expression is very simply, if you knows how to perform different operations like addition, subtraction, multiplication, and divisions. All the operations are very simple and you have learned how to solve the problems of such type of operators in the early classes. This is the time when you have to implement that properly and solve different types of problems. In this article I will teach you how to simplify numeric expressions you can easily solve them by performing simple operations. Order of process is used when one or more function is included in any problem. We use three rules in order to deal with such kind of problems in order of operations.

> First one is perform the action within the parentheses.  

> From left to right order, do all the multiplication and division function.

> Finally do all the addition and subtraction operations from left to right.

Let’s have few examples of the numerical expression and see how to apply above mentioned rules on the numerical expression.

Example: Simplify the numerical term in the expression 11+ 7 x (6 + 3) ÷ 9 - 8 using the order of operations.

Solution:

In this problem all the four symbols are present; we have to do all the four operations that includes: additions, subtraction, multiplication, division operations here.

= 11 + 7 x (6 +3) ÷ 9 – 8

=11+ 7 x 9 ÷ 9 – 8

= 11+ 63÷ 9 – 8

= 11 + 7 – 8

=18 – 8

= 10

Answer: 10

In this way we simplify the numerical expression. In the above expression we first solve the parentheses then on the priority basis we first perform the multiplication operation, then division after that addition and in last subtraction operation.

Example 2:

Solve the numerical expression 100÷ (13 + 3 x 9) - 2 using the order of operations.

Solution:

In this expression we are having all the four basic mathematical operators. So we have to perform all the four operations.

= 100 ÷ (13 + 3 x 9) – 2

=100 ÷ (13 + 27) – 2

= 100 ÷ 40 – 2

= 2.5– 2

= 0.5

Answer: 0.5

Example 3:

Get the answer of the given numerical expression 55 - (8 * 9 - 7) + 2 using the order of operations.

Solution: In the above mentioned expression we are having three operators and according to rule we first solve the parentheses then multiplication, after that addition and finally subtraction.

= 55 - (8 * 9 - 7) + 2

= 55 - (72 - 7) + 2

= 55 - 65 + 2

= 55 - 67

= -8

Answer: -8

Example 4:

Evaluate the numerical term in the expression 3 + 5 (2 + 4) - 7 using the order of operations.

Solution:

Since all the four symbols are present in the given expression, we have to do all the three additions, subtraction, multiplication, division operations here.

=5 + 5 ( 2 + 4 ) - 7

= 5+10+20 -7

= 35-7

= 28

Answer: 28

In this way we deal with the different type of numerical expression and simplify them to the simplest form. Whenever you deal with simplification of numerical expression always remember the order of operation rule and solve the problem using the same rule. If you don’t use the order of operation rule than the simple problem become the complex one and difficult to solve.

Now, talk about the other important topic that you study in grade VII i.e monomials.   

A monomial is that term which is comprised of a combination of the following: numbers, variables, and exponents. In algebraic expression and equations, terms, or monomials are separated by addition (+) and subtraction (-) symbols. In simple terms we can define a Monomial as an algebraic expression with only one term.

For instance, 7ab, – 5p, 3z2, 4po, 5 etc.

Monomial may have a constant or variables or both. To denote variables we use letters a,b,c ,d, x, y, l, m, ... etc. A variable can take various values; its value is not fixed. On the other side. a constant has a fixed value such as: 4, 500, 678,12432535, 100, –17, etc.

Let’s put some light on the examples of Monomials

1. 19xy
in this, Coefficient: 19 , variables x and y and exponent 1

2. -2ab2
in this expression  Coefficient: -2 , variables are ‘a’ and ‘b’ and exponent is 2

3. 41 ab3
Coefficient: 41 , variables are a and b and exponent is 3

4. xa2
Coefficient: -1 because -x2 is the same as -1x2

Variable is x and the exponent is 2.

Let’s switch to the point that what operations can we perform on Monomials,

1.    Addition and Subtraction of Monomials: When terms or monomials contain the same variable and same exponent, they are similar terms.

Addition and subtraction of monomials is done by combining the like terms. In addition we add the similar terms and in subtracting we subtract the similar or like terms.

Simplify the following expressions.

1)      7 + 7x +13x

In this simply add the x terms and leave the other terms as it is,

 20x + 7.

2)      -12c + 12c,

In this we are having both terms as the co-efficient of the c one co-efficient is -12 and other is 12. On simplifying the term we get 0.

3)      8y - 3y

Both the terms are of y on adding we get 5y.

4)      x2 + y2 + x

we can’t simplify the above problem further as there is no like present in the Monomial.

Multiplication of Monomials: When you multiply the monomial, first step is multiplying the numerical coefficients (for e.g. 4 and the 8) and then multiplying the literal coefficients or variables (a and b). in the second step you need  to multiply the similar variables by adding their exponents (for e.g. 3+2). (Rule am * an = am+n).

Simplify the following monomials:

1) 5 ab * 5 b = 25 ab2

2) 2 xy * 3 yz = 6 xy2z

3) -4 x6 * 6x2 =  -24 x8

4) 4 b5c * 7 ab2c = 28 ab7c2

5) 20 ac * pq = 20acpq

Division of Monomials: When we perform this operation of the monomial the very first step is dividing the numerical coefficients (for e.g. 24 and 8) and then dividing the literal coefficients or variables (a and b). Second step is to divide the like variables by subtracting their exponents (for e. g. 5-2 ). (Rule am / an = am-n).

Simplify the following monomials:

1) 25 pq / 5 q = 5 p

2) 15 ab4c / 3 bc = 5 ab3

4) 49 x2y5z / 7 xy2z = 7 xy3

5) 20 ab / ab = 20

 

 

 

 

Sunday 18 December 2011

Graphing Data in Grade VII

Hello friends! Today we will discuss two interesting topics of algebra that you study in grade VII. The first topic that we will cover today is Graphing data to demonstrate relationships and the next will Arithmetic sequence. Graphing is a simple pictorial representation of any data on the number line. With the help of graph you can easily understand and easily analyze the data.  Data recorded in experiments or surveys is exhibited by a statistical data graph. We use different variant types of graphs for the representation of the statistical data graph. Mainly, we have eleven types of graphs that we generally use for the representation of the statistical data.

  1. Box Plot: It is a convenient way of graphical representation of data or we can say it is a way of summarizing a set of data measured on an interval scale. It is sometimes used for the exploratory data analysis.  In box plot graph we show the shape of the distribution, its central value, and variability.
  2. Stem and leaf plot: this is a method used for showing the frequency with which certain classes of values occur. In this we can make a frequency distribution table or a histogram for the values, or we can easily use a stem-and-leaf plot graph method.
  3. Frequency polygon: it is a graphical display of a frequency table, in this intervals are shown on the X- axis and the number of scores in each interval is represented by the height of a point situated above the middle interval. The points are connected in such a way that together with the X-axis they form a polygon.

 

  1. Scatter plot: it is a graph in which we use Cartesian coordinates to display values for two variables for a set of data. The data is represented as a collection of pints, each having the value of one variable determining the position on the horizontal axis and the value of the other variable determining the position on the vertical axis.   
  2. Line graph: this type of graph displaying data or information that changes continuously over time.

 

 

  1. Bar graph: A bar chart or bar graph is a graph with rectangular bars with lengths proportional to the different values that they represent. The bar graph can be plotted on horizontal axis or on vertical axis.
  1. Histogram: it is a graphical representation of data that shows a visual impression of the distribution of data.

 

  1. Pictograph: They are often used for the representation of the data in graphical form.
  2. Map graph: This type of graph is also called as the grid system. in this is the standard grid of up and down drawn lines and left and right drawn lines creating a grid of intersecting lines.

 

  1. Pie graph: The pie graph is the most commonly used statistical charts for the representation of the business data and the mass media data.

 

  1. Line plot: it is a graph that shows frequency of data along a number line. It is one of the best way for the representation of the data.

 

 

 

In Grade VII, students learn histo graphical representation of the data, frequency polygon and the bar graphs. In Statistical data graph, a histogram is used for the representation of the two dimensional data used to graph continuous data. Histograms do not have spaces between the bars.

Here is an example in which you see how to represent data in form of histogram graph.

 

.

Data

Frequency

0-10

5600

10-20

5250

20-30

4750

30-40

3750

40-50

3500

50-60

2750

60-70

2600

70-80

2750

80-90

2500

90-100

2400

histogram data graph

Next method is frequency polygon, in this we use to study the graphical representation of a frequency table. This type of graph offers approximate smooth bend that explains a frequency distribution if the class intervals were to be made as small as possible.

The study of points is involved so that collectively with the X-axis they form a polygon.

Statistical data graph in Frequency polygon problem:

Construct the Statistical data graph using Frequency polygon.

Data

Mid term value

Frequency

0-2

1

1

2-4

3

12

4-6

5

9

6-8

7

1

8-10

9

1

Graph:

 

Data Graphs Using Bar Graphfrequency polygon data graph


Other graphs that you study in the same class is called as bar graph as I already mentioned earlier in the article that what it is? Let’s take an example of this, and see how to plot such kind of graph.  These graphs are one of the most interesting topic that you can easily plot.

 

Here is an example of construction of bar graph for the statistical data graph.

Brain region

Receptor Binding

1

35

2

50

3

28

4

20

Graph:

Graphing data using bar chart

 

This is all about the different types of graph that you use for the demonstration of the data. Now, we will switch to the next topic that is Arithmetic sequence. It is also known as the arithmetic progression, or arithmetic series. An arithmetic sequence consists of the sequence of numbers and accept the first term,  remaining terms can be obtained by adding one number to its preceding number. It is denoted as the arrangement of two consecutive numbers, the progression which is constant.  Other than AP we also have other type of series called as geometric progression, harmonic progression. You will learn all these in the future grades.

 

 

Arithmetic progression also have its own general form, if you see any such type of equation then understand that it is in form of A.P. The general form of an A.P. is given as:

 

a = first term, d = common difference, then A.P. is a, a+d, a+2d, a+3d,.....

In this every time you will observe that in any term the coefficient of d is always less by one than the number of terms in the series.

Thus, second term is a+d

third term is a+2d

fourth term is a+3d

tenth term is a+9d

and generally, nth term is a + (n-1)d.

If n is the number of terms and if tn is the nth term, then tn = a+(n-1)d.

 

 

In arithmetic progression common difference is calculated by subtracting any term from the series from the intermediate succeeding them.  Let’s see few examples of the arithmetic series.  

See the following series and find whether it is a A.P. or not?

i) 1, 3, 5, 7, …

In this example, common difference in the first sequence is 2 and each term in the first sequence is succeeding with the increment of the two and thus forming an arithmetic sequence.

ii) 3, 7, 11, 15, …

In this there is difference of 4, in all the terms present in the series. You can easily found the nth term by adding 4 in the n-1th term.

iii) 15, 12, 9, …

This is also in form of arithmetic progression; in this each term is decreasing by 3.

iv) x, x - d, x - 2d, .....

in the fourth it is -d

v) p , p + q, p + 2q, p + 3q,..

In this each time there is increment of q. so the series is in form of A.P.

We can also calculate the sum of the Arithmetic progression. The sum is some sort similar to normal addition, let’s have a look on how to do addition of the arithmetic sequences.

Let a=first term, d=common difference, l=tn=last term, s=required sum. Then,

S= a + (a +d) + (a + 2d) +(a + 3d)+…..a + (n -2)d + a+(n-1)d

If we write the same series in the reverse order then we will get the sequence as:

 

S= a +(n- 1)d+ a+(n - 2)d+….+ a + d +a

Adding together the two series we will get the answer as:

2s = [2a +(n-1)d] + [2a + (n-1)d] +………up to nth term.

2s = n2a + (n -1),

S = n/2 2a + (n -1)d,

S = n/2a + a+(n-1)d

 

S = n/2(a +1),

Here, l = a + (n -1)d

 

Now have a look on the properties of the Arithmetic progression.

 

If p, q, r, s are in A.P., then

1: p +- k, q +- k, r +- k, s +- k,… are also in arithmetic progression.

2: kp, kq, kr, ks…. will also be in A.P.

 

 

A remark on finding a few members of an A.P. whose sum is given along with other conditions:

  1. If the sum of three numbers in A.P. is given, take the numbers as a-d, a, a+d.
  2. For the five number series always take take them as: a – 2d, a –d, a,  a+d, a +2d.
  3. If you have to take a four numbers series then always take them as: a- 3d, a – d, a +d, a + 3d.
  4. For any six term, take the series as: a – 5d, a – 3d, a – d, a+ d, a +3d, a +5d.

This is all about arithmetic progression. Using the above mentioned form, series, formula and properties you can easily solve different type of arithmetic progression problems.

Saturday 17 December 2011

Systems of Equations in X Grade

Hello my dear friends today we will learn few interesting topic of grade X that are imbibe in Algebra. Algebra is a very large subject that has lots of topics and you can easily learn them with intuition. Mathematics is that subject that can only be learnt if you have intrusion and is considered as one of the most interesting and important subject. Many students are math phobic and they always try to move away from this subject. Friends no need to get afraid of this wonderful subject you can easily learn this subject with help of you teachers, tutors and me. In this article we will focus on changing parameters of function, and system of equations. Before this in the previous sections I made you familiar with other math topics like, Different forms of numbers, Scientific notation, square roots, exponents, radicals, absolute value, factorial, logarithms., Properties of numbers, Estimation of solutions, Sequences and series Proportionality/direct variation, and exponential/fractional expressions.

 

Now, start talking about our today’s topic i.e. changing parameters of function. First talk about the parameters, in common meaning, the parameters are used to identify a characteristic, a feature, a measurable factor, which can be used to define a particular or specific system. For the evaluation or for the comprehension of an event, or a project or any other such type of situation, parameter is an important element. If we talk about parameters in Mathematics then a parameter is a defined as a quantity that serves to relate different functions and different variables using a common variable when such a relationship would be difficult to explicate with an equation.

 

Different Mathematical functions have one or more arguments that are designated in the definition by variables, on the other side their definition also have parameters. In the list of arguments variables are mentioned that the functions takes, but the parameters are not mentioned. When we define parameters or any parameters present, the definition actually defines a whole family of functions, one for every valid set of parameters value. We can take the example of the general quadratic equation form: that defines the function and parameters.

F(x) = ax2 +bx +c,

In this equation, variable x designates the function argument, but a,b, and c are parameters that determine which quadratic function one is considering. The Parameters could be incorporated into the function name to indicate its dependence on the parameter. To understand this we can take example of log, such as: 

loga(x) = log (x)/ log (a),

In this ‘a’ is a parameter that is indicating which logarithmic function is being used. Here ‘a’ is not an argument of the function.

 

Parameters varies from function to function, in Grade X, you commonly use population parameter. A quantity or statistical measure that for a given population which is fixed and that is used as the value for a variable in some of the general distribution or frequency function to make it is a descriptive of that population.The variance and the Mean of a population are referred as the population parameter.

The next topic that we will discuss today is called as system of equations. A system of equation means a set or a group of equations and sometimes we refer this as simultaneous equations also. In this we have more than one equation with multiple variables and we try to solve the equation in order to calculate the value of the all variables. Linear equations are very simple if we compare them with non-linear equation and the simplest linear system is one with two equations and three unknowns or variables. In simple words we can define the same as a collection of two or more equations with a same set of unknowns. For the solution of system of equations, we need to find values for every of the unknowns that will declare every equation in the system. When you deal with system of equations you can either have linear equation or non-linear.

 

Now, let’s focus on the types of systems of equations. In grade X you will learn Elimination, Substitution, linear equation, matrix, and consistent equations. Now, have an introduction of all the topics that I mentioned here. First talk about the elimination method or elimination technique, it is considered as one of the algebraic method that we use for solving the system of equations. In elimination method we perform operation on the one equation the operation may be of adding some number or multiplication, etc. we perform this operation in order to cancel one of the variable and with this we can easily find the value of other variables.


The next one is Substitution method, this method the algebraic expression of one of the variable is substituted in another equation at the place of the respective variable and then the variable is used to solve, when we solve the variable we get the numeric value and then easily with its help we can solve the different problems. by substituting in any of the equation the value of the second variable is also found easily.  The third one is Linear equation, this is also considered as an algebraic expression, which relates the two different types of variables and produces a graph which is always in the form of a line.

Fourth one is Matrix, it is a rectangular array of numbers and in this we use to write numbers inside the bracket. Matrix method is used to find the solutions for complex systems of equations. The last one is called as the consistent System.  In this we have set of equations whole solution set is represented by only one ordered pair. Here are few examples for you students so that you can easily understand how to solve the system of equation. Examples are the best way to understand different type of problems and with this you can solve multiple problems in an easy way.

 

Here, is the very first and simple example, give the solution of the problems and tell whether it is example of system of equation or not.

y + 21 = 71

Solution:

This is a simple example of linear equation as only one equation is given but in system of equation we have more than one equation that either is two, three or more. We need not to implement any of the above mentioned method in this as we can easily solve the problem by subtracting 21 from both the side of the equation.

 Y + 21 – 21 = 71 – 21,

Y =50,

In this way we can easily calculate the value of the unknown in this equation.

Now, here is another example for you. Give the solution of the problems and tell it is system of equation or not.

Example: b = 2a + 1, 2b = 3a – 2

Solution: this is a system of equation as it is having two equations, and for solving this problem you can easily use any of the above mentioned method which we use to solve the system of equations. Let’s use the substitution method and find the solution of this problem.

Step 1: substitute the one equation to another equation like:

2(2a + 1) = 3a – 2,

Step 2: now, we have single variable equation, we know how to solve that variable equation as the equation is now in form of single variable which you can easily solve and find its value.

4a + 2 = 3a – 2,

4a – 3a = -2 – 2,

a = -4,

In this way we find the value of the one variable now you can easily find the value of the other variable by putting the value of ‘a’.

Step 3: to find the value of b  put value of a

b = 2a + 1,

b = 2(-4) + 1,

b = -8 + 1,

b = -7,

Thus we find the value of ‘a’ and ‘b’ using substitution method.

One more example of the system of equations and solve this problem using the elimination method.

Example: 2p + 2q = 4

          4p – 2q = 8.

Solution: As there is two equation given to us, so we can easily say that it is a system of equation having two variables p and q.

Step 1:

2p + 2q = 4.

4p – 2q = 8.

Step 2: in this subtract equation 2 from equation 1 and on doing this we get,

           6p = 12

Step 3: now, divide both the side by 6, on doing this we get

p = 2.

 

Step 4: now, replace p with its value in the equation 1, when we do this we easily calculate the value of the other variable q.

 

 

 

4p – 2q = 8.

4(2) – 2q = 8.

8 – 2q = 8.

q= 0.

Now, we have both the value of p and q

(p, q) = (2. 0).

In other method you will study in the higher classes.

 

Keywords:

Monday 12 December 2011

Measurement in Grade VII

Hello friends, today I will make you familiar with few interesting math topics that you study in Grade VII. Today, we will go through formulas for measurements, graphing data to demonstrate relationships and Arithmetic sequences. Before, this I will make you familiar with the starting topic of Grade VII that you study in Algebra like:   Problems involving positive/negative powers and solving problems in percent; proportional relationships. After the brief introduction of what you study today let’s move on the topic. The very first topic that we will study today is Formulas for measurement. In this we study the different formula that are used for calculating different things like we learn the formula that are used to calculate the area of square, circle, and etc. not only you learn formulas but you also learn how to calculate them using the formula.

Let’s start with the circle and see its different formula used to calculate different things. We use several terms when we deal with circles like circumference, diameter, radius and many other. Circumference is the distance around the circle and the diameter is defined as the distance across the circle. The radius is generally defined as the half of the diameter or we can define it as the distance from the center to a point on the circle.

The different formula of measurement related to circle is circumference, radius and diameter. The radius is defined as ‘r’ and the diameter is defined as ‘d’ and d = 2r.

Circumference of circle (c)= pie(d) ,

                                         = pie(2r)

 And the area of circle is given as(A) = pie(r2) the value of pie is equivalent to 3.14.

For example r = 2cm, then calculate the d, c and A of the circle.

As you know d =  2r, so,

D = 2 X 2 cm,

D = 4cm,

C = pie(d) so,

C = pie X4,

C= 3.14 X4,

C = 12.56 cm. and in the same way Area(A) = pie(r2),

So, A = 3.14 X 2X2,

A = 12.56 cm2.

 

In this grade kids learn formula for the rectangle also. The volume of solid rectangle is calculate with help of formula given as:

Volume = Length X Width X height

V = lwh

And the surface formula is give as: 2lw + 2lh + 2wh.

Let's see an example that how to calculate the volume of rectangle. Suppose you have length = 12, breadth = 2, and height = 5, and we can easily calculate the volume by putting the values in the formula, like

V = lbh

= 12 cm X 2 cm X 5 cm,

= 120 cm3.

If we have measurements in different units then first change all of them in same unit and then only apply the formula on the given terms. If we don’t take all the terms in the same form then you will not get the right or correct answer. In order to get the correct answer analyze the problem properly and then implement it in the formula.

Next formula for measurement we will study abiut the Trapezoid, its Area is given as: (b1 + b2/2) X h.

Perimeter of Trapezoid is given as: area +b1 + b2 +c

or,

P = a + b1 + b2 +c.

 Students of class VII also learn formula for calculating different measurement like Cylinder and Cones. The Volume of Cylinder is given as: pie(r2) X h.

The surface formula of Cylinder is: S 2(pie) r X  h or

S = 2(pie)rh + 2(pie) r2

The cone volume is calculated with the following formula:

Volume = 1/3 pie r2 X h,

V = 1/3pier2h .

The Surface is calculated with help of S= (pie)r2 + (pie)rs

S = pie r2 + pie rs .

Let’s see an example of cylinders and see how to determine its surface. Suppose we have r = 5cm and h 8cm, then we can easily determine the surface of the cylinder using the formula:

The surface formula of Cylinder is: S=  2(pie) r X  h

Put all the given values in formula and doing so we get,

S = 2 X 3.12 X 5 X 8,

S= 251.2 cm.

In this way you can easily calculate the surface of the cylinder. Using different formula for measurement you can determine different things like volume, surface, area, circumference and etc.

Now, move to the next topic we will study today it is called as Arithmetic sequence. In mathematics, this sequence is defined as a sequence of numbers that has a constant difference between every two consecutive terms. In  simple words we can define the same as a sequence of numbers in which each term except the first term is the result of adding the same number, which is called as common difference, to the preceding terms.

Let’s see an example of the topic that my dear students can easily understand the topic properly and easily and examples are the best way to clear your doubts and concepts. The following examples are problems involving arithmetic sequences

Problem Number One:

 

The sequence 5, 11, 17, 23,….. is an arithmetic sequence in which the common difference between each term is of 6. And if 6 is added to each term of the sequence it gives the next number of the sequence.  Arithmetic series is defined as the indicated sum of the terms of an arithmetic sequence. The sequence 5, 11, 17, 23, 29, 35 is an arithmetic sequence. 5 + 11 + 17 + 23 + 29 + 35 is the corresponding arithmetic series.

 

In arithmetic sequence to calculate the nth term of the series we have a formula, which is given below:

An = A + (n - 1) d

Where, An = is the nth term, in the case of our problem it is the 40th term

A = the first term of the sequence , in our problem it is 2.

n = number of terms, in our problem it is 40.

d = the interval of the terms, or the difference of the next term.

Let’s see an example and implement the above formula in order to calculate the nth term.

Question: We have first three terms of an arithmetic sequence as 2, 6 and 10, then find the 40th term?

Answer: using the above formula, An = A + (n - 1) d

We can determine that what is given to us and we first we calculate the value of d.

To get d; d = 6 - 2 = 4.

A = 2,

n = 40,

and d = 4

Now, substitute the different values in the formula and we will get the final answer:

An = 2 + (40 - 1 ) 4

An = 2 + (39) 4

An = 2 + 156

An = 158.

The 40th term of the arithmetic sequence is 158.

Now, see one more problem of the Arithmetic sequence, suppose we have first term of an arithmetic sequence is -3 and the eighth term is 11, find d and write the first 10 terms of the sequence.

Solution: in the above problem we have,

A = -3,

n = 8 

A = 11

On substituting these values in the formula we will get,

11 = -3 + (8 - 1) d

11 = -3 + 7d

14 = 7d

d = 2

The first ten terms are -3, -1, 1, 3, 5, 7, 9, 11, 13, 15

 

After this move to other topic of Arithmetic sequence, it is called as sum of arithmetic sequence. Sum of the first ‘n’ terms of an arithmetic sequence with first term A and nth term An is;

Sn = n/2 (A + An) or this formula maybe rewritten as

Sn = n (A+An)/2

In the simple terms we can define the same as: "the number of terms multiplied by the mean value or average of the first and last terms."

If we have any arithmetic sequence with the first term A and common difference d, then the sum of the first n terms is given as:

Sn = n/2 2a + (n - 1 ) d

Now, see one more example to understand this concept.

Question: Determine the sum of all the odd integers from 1 to 1111, inclusive.

Solution :  in order to calculate the solution of the above problems we can simply use the following method,

Since the odd integers 1, 3, 5, etc, taken in order from the arithmetic sequence with d = 2, we can first find n from the formula for the nth term;

1111 = 1 + (n - 1) 2

1111 = 2n -1

1112 = 2n

n = 556

S = 556/2 ( 1 + 1111)

= 278 ( 1112)

= 309, 136.

In this way we get the solution of the above problem. Hopefully you understand both the topics that I taught you today. In the next section we will put light on some other interesting topics.  

Sunday 11 December 2011

Powers in Grade VII

Hello friends! Today we will learn the very first topic of Grade VII that is included in algebra. Algebra is a vast subject and students of this grade learn several topics in algebra that includes Problems Involving Positive Powers/Negative Powers, Solving problems in percent; proportional relationships, Formulas for measurement, Graphing data to demonstrate relationships, Arithmetic sequences, Simplifying numerical expressions, Operations on monomials, Linear/non-linear functions, equations, inequalities and Multi step problems. In this article we will discuss about problems involving negative and positive powers. Whenever we have terms raised to a number generally, we call them as exponents. The power raised to any number if contains negative sign then it is called as negative power problem and if the power raise to any number is positive then it is defined as the positive power problems.


Let's start the topic, you always write, 20 = 1 do you have any reason why we define 20 as 1 and what does a negative exponent mean? Whenever any number contains zero in its power it means that its value is one. Like 20 , 30 , 40, and so on will give answer as one only. You all know that exponents represent the numbers of times you have to multiply a number by itself. For illustration let's see an example: 3this term means 3 raised to power 2. to simply the term we can write it as: 3 X 3 which will give result as: 9 similarly if we have 25 = 2X2X2X2X2. The positive power of any number represents the exact number of multiplication that a particular number have to go. This is the case when we have positive powers but what about negative powers? Like if you have 3-2, then how you will multiply three with negative two times.

A negative exponent is equivalent to the inverse of the same number with a positive exponent. For example: x-7, then it can be written as:

x-7 = 1/x7

You can easily solve these problems there is nothing special in case of negative power problems. It is a simple intermediate step which you may use. The best way to solve negative power problem is to work out lots of examples that will help you in solving lots of problems directly.

X-n = 1/Xn and 1/X-n = Xn,

Whenever you solve any problems related to powers be careful with negative power problems. The temptation is to negate the base, which would not be a correct thing to do. As you all know exponents are the other way to write, multiplication and the negative is in the exponent, to write it as a positive exponent we do the multiplicative
inverse which is to take the reciprocal of the base term.

Here, are few example of the positive power, like: 25 = 32, 24= 16,
and tell what is 23= ? , 22 = ? , 21 = ? and 20 =?. to solve such type of problems simply multiply the terms up to total number of powers,
like: 23 = 2 X2X2 = 4 X2 = 8, similarly, 22 = 2X2= 4, 21 = 2. And any number having power as zero we give answer as one always.  Let’s take another example of this, 4this can be written as 4 X 4X 4 X4= 16 X16 = 256. Whatever power is given to you simply multiply the number that much of times. When you do this you will easily solve the problems related to positive powers. In the same way we can have other such types of problems such as: 35 = 243, in this we multiply 3 five times. In this we will do 3X3X3X3X3= 243, as 9X3X3X3= 9X9X3= 81X3 = 243. In this way we can easily solve the problems related to exponents having positive powers. Students can try negative numbers i.e. negative base. You just divide by that negative number at each
step. For example: -25  = -32,  similarly, -2= 16, -23= -8, -22 = 4. In case of positive powers but negative base
we multiply the numbers as in case of positive powers only but, in this case you have to see whether the power is positive or negative. As you all know when we multiply to negative numbers they give positive result, this is defined in the rules of the mathematics. The other rule defines that if we have odd number then it gives the
negative output. Apart from this, you all must have read few other rules like:

-* - = +,

-* + = -,

+ * + = +,

+ * - = -.

These are the four main rules that are used throughout your mathematics. Whenever you solve any problem of mathematics the above rule plays a very vital role. So, friends whenever you multiply any number having such symbols, try to solve them following the rules. In case you multiply any number and calculate the answer correct and put the sign wrong then your answer is considered as wrong. Like: 2 * 3 = 6,
2 * -3 = -6,
-2 * 3 = -6, and -2 *-3 = 6

In this we see how an answer changes with the change of symbols. The simple multiplication can result different answers when its symbol changes.

Now, after this again move to our main topic of today. Negative powers, in this the power is negative base may or may not be negative as it depends on the problems. As I mentioned earlier that if we have X-n =
1/Xn,  whenever we have negative power we take the term in the denominator and numerator is considered as 1in the above example. Let’s take few examples and understand the concept of negative powers properly. Suppose we have: 10-2

In this case we take 10 to denominator and then solve the problem,
1/102, Now, multiply the 10 with 10 this will give us: 1/10*10 = 1/100. In the same way you can solve many other problems like 2-2. In this you can easily multiply the 2 with 2 by taking it to the denominator as

½ * 2 = ¼, In the same way we can multiply other negative power sums by taking the negative term to the denominator and solve several math problems in seconds. Suppose if we have negative base and negative
power then how you will solve such type of problems. To understand this problem let’s take an example: (-3)-2 = 1 / (-3)2 = 1/9. In this we follow the same rule of negative power as I explained earlier and the concept or we can say rule of the operators. Example: (- 4)-3 = 1 /(- 4)3

In this we have power 3 so, 1 / -4 * -4 * -4 = 1/ -64.

As the power is odd so we get the sign of minus and if power is even we will get positive sign when base is negative.

Now, focus on few more example: simplify: 1 /(3) -3

In this question we are having negative power in denominator in this case we will solve the problem as first taking the denominator and convert it in numerator  so that power will become positive, as 33
now simply multiply the positive powers as 3 * 3 *3 = 27.

Suppose we have z3 . z-5

This means we have z (3) + (-5) 
= z-2

= 1 / z-2

Let’s have a complex example of this power problem: (x4 y3/ 2z2)-1  in this we have raise each base to -1.

(x4 y3/ 2z2)-1
 = x(4 * -1) y (3 * -1)/ 2 -1 z(2 * -1),

= x-4 y-3 / 2-1 c-2 = 2c2 / a4 b3.
In this way students you can easily solve the several math problems having powers.  Practice such type of problems and become master of mathematics. Negative powers and positive powers are used throughout mathematics in solving thousands of different problems. You can use this in solving differentiation and integration problems also. I tried my best to clear your doubts about this topic; still you have any problems then clear all your doubts and understand the concept properly so that you will not face any problem in future.

Students can take help of online tutors in order to learn different mathematics topics and in order to solve the several problems students can switch to online solvers and other tools. Friends do regular practice of different topics and become the master of mathematics. Practice is the main key to success, if you want to solve all math
problems and to score good grades do regular practice and feel how interesting is mathematics and how simple it is. In the coming articles we will discuss about, other algebraic, geometric, probability, statistics topics and I will make mathematics very easy for you. So practice negative and positive powers till we come with new problems
and topics. Enjoy mathematics!!

Thursday 1 December 2011

A brief introduction to Grade VII math Curriculum

Hello friends, today we will discuss about the math topics that you study in Grade VII.  In this class students of age group 13-14 study. Mathematics is study of quantity, structure, space and change which we learn in different branches of mathematics. In this article I will give you a brief introduction of topics that students learn in grade VII. With this I will also tell you how to learn mathematics. In grade VII students go through many new topics and study few previous one’s in detailed form.  In this class students learn Algebra, Geometry, Measurement, Numbers and Operations, Probability and Statistics, and with this students go through important topics that they have covered under 6 Grade Math. Many students are math phobic and they just hate this subject because they think it is the worst subject of their course. The reason behind this is that they don’t understand its fundamental principles and because of this they lack their interest in particular subject. Now, let’s switch gear towards the topics that you are going to learn in grade VII. Here, we have a brief introduction of Grade VII mathematics syllabus.

 

Let’s start with algebra. It deals with the relationship of operators and numbers which also posses constants. In grade VII students learn several topics that involve problems involving positive/negative power. In this you learn how to solve the problems having negative terms in the exponents or powers. Next topic is solving problems in percentage; proportional relationships, formulas for measurement, and graphing data to demonstrate relationships.  Arithmetic sequences, in this data are represented as a sequential manner, simplifying numerical expressions simply involves the solving of expressions, operations on monomials, linear/non-linear functions, equations, inequalities. In this, students learn what inequality equations are and how to solve them. What is an inequality do you know, it is that equation which contains greater than and less than symbols. In Grade VII you will learn this topic in detail and also learn how to solve its problems using different methods. With this, students learn, multistep problems and how to solve a problem in different steps using different methods.

 

After, algebra let’s talk about the other pure branch of mathematics i.e. geometry. It is defined as a branch of mathematics that deals with the designing of different shapes, calculation of their area, depth, volumes, height, etc. In the VIIth grade mathematics students learn how to solve different geometrical problem, like Complementary/supplementary angles: in this students learn different types of examples and how to solve problems related to complementary/supplementary angles. Next topic of geometry involves properties of 2-D and 3-D figures, Rectangular coordinate system, reflections/translations on a coordinate plans, sketching and modeling, regular/irregular geometric shapes, different geometric concepts, tessellations, properties of lines and basic construction.  Tessellations, is a way to tile a floor with different shapes so that there is no overlapping and no gaps. In geometry section students of the Grade VII also learn Pythagorean Theorem, Congruence, relation between objects in space, and graphing solutions of inequalities.  Geometry is one of the interesting branch that you study and you enjoy solving geometrical problems.

 

 

Next topic that you will go through is measurement, problems in measurements, formulas for measurement, scale drawings, significant digits, and relative error and magnitude. In this class students learn what the different units of measurements are and how to convert them from one unit to other. Students learn the units of time, metric system, mass, length, volume, and temperature conversions. In scale drawings you will learn how to represent them on graphs as a map cannot be of the same sizes as the area it represents. So we use scaled down measurement to make a map. The next topic that we study is significant digits. In this you will learn how a number is expressed in scientific notation. The number of significant digits is the number of digits needed to express the number within the uncertainty of calculation.

 

In the number and operations students learn Rational numbers, problems involving markups, commissions, profits, operations on fractions, decimals, integers, rates and ratios, order of operations, exponents, scientific notation, radicals, absolute value, irrational/real numbers, number systems, Positive/negative numbers - inverse relationships,  Estimation of solutions,  Primes, factors, multiples, number sequences,  Simple/compound interest, Probability and Statistics, Simple/composite experiments, independent events, odds for and odds against,  Representations of data, and  Mean, median, mode, and range. Rational numbers are those numbers that can be formed by dividing one integer by another. And this word is derived from ratio. In this class you will learn this topic in detail and see how the problems can be represented in rational forms. In previous class you all have gone through fractions. In grade VII you will learn how to perform different operations on fractions and simplify them. As I mentioned several topics you will also learn how to get the solution of a problem, and what will be the estimated solution of a problem. 

 

In later grades you will learn statistics and in grade VII you will learn the basic like what is mean, mode, median, range and how to solve problems related to them. Mean is defined as average and you all are familiar with average. Mode is simply the most repeated term in the given series or list while median is the middle number in odd list and average of middle two numbers in case of even list.

 

Apart from all the above described topics, students of Grade VII do revision of the topics that they had learnt in pervious classes like,  Number system (whole numbers, decimal numbers, rational numbers, integers, fractions and ordering the numbers), Measurement (metric system, temperature, mass, volume, length, time, area, surface area, and perimeter), Basic geometry (understanding the elementary shapes, ideas and geometric figures),  Basic Algebra, Data handling in statistics and Symmetry, Ratio and Proportion. You all learn these topics not only in class VI but also in previous classes and in this class you will get a brief gist of all these topics as all the topics of mathematics are interrelated and all previous concepts must be clear in order to learn the new concepts.

 

Generally students having common mentality related to mathematics, according to which students always move away from this interesting subject.  Mathematics is a subject that is full of concepts that are used throughout the life.  Math is that subject which is most commonly used in day to day life. If you want to become master of any subject, then all your concepts must be clear. And how the concepts get clear? Confused that how to clear the concepts. To clear your concepts you need to do a regular practice.

 

You all must have heard a very common proverb that says, practice make a man perfect. In order to get perfection you need to do practice on regular basis. Do practice of all the topics and solve your problems on the same day.  Many students shy to ask their problems to teachers in class room because they think other students will make fun of them that they don’t know such a small thing. But, kids, you should have courage to clear all your doubts as if you don’t do this then it will hamper you and your study not others. Try to overcome your problems when they occur rather than postponing them for future and making them complex. As you all know math is a conceptual subject and all the concepts are interrelated to each other. If your any concept is not clear or you are facing problems in any concept than it will definitely create problems while you learn other concepts and solve problems.

 

Students I am here, to solve all your mathematical queries as I will help you in learning different mathematical concept and make you familiar with different kind of examples on a single topic so that you can easily catch the concept of the problem s and method of solving the problem.  If we consider a small problem complex and before making any effort to solve the problem we think we can’t solve it then you won’t be able to solve the problem in your life. So try to solve each and every problem and if you have any problem then take help of your teachers tutors or you can also switch to online help. You have to make little efforts with your teachers and tutors and you can easily learn this subject. So kids, learn mathematics in proper way and solve all your problems. 

 

One more common issue arises with most of the students that they don’t like to do their homework. Homework is given to students so that they can practice the topic taught to them in class but most of the students copy it from other students’ copy. Kids, try to do homework yourself if any problem occur then take help of friends, tutors or online help.

 

 

Wednesday 30 November 2011

Linear/non-linear functions, equations, inequalities for Grade VII

Linear functions: 

Functions which have x as the input variable, where x has an exponent of only 1.

For example:
y = mx + c
Here we can see that x has an exponent of 1 in each equation.

The above functions such as this yields graphs that is straight line, and, thus, the name linear is alloted to it.

 

Linear functions are of three categories:

1) Slope-Intercept Form

2) Point-Slope Form

3) General Form


 

1) Slope-Intercept Form

A simple way to define a linear function is through the slope-intercept form of a linear function. When drawn on a common (x, y) graph it is given as:

y = mx + b

Or, in a formal function definition:

f(x) = mx + b


 

Basically, this function describes a set, or locus, of (x, y) points, and each of these points are located in a straight line. 'm' represents the slope of the line. 'b' represents the y-coordinate for the spot where the line crosses the y-axis and this point is called the 'y-intercept'.


 

2) Point-Slope Form

In the 'point-slope form' for the equation of a line, the definition does not start with 'y =' or 'f(x)=', so it's not written in a common function definition form.

But it can be very well written in algebra:

y = m(x - x1) + y1

and as a functional definition it can be written as:
f(x) = m(x - x1) + y1

To conclude the equation with the given slopes and points, we can say that the variable m is the slope of the line and the point x1, y1 are the points on the line. If anyone knows the slope of and the coordinates for one point on the line, then the he or she can include or can enter those values into this equation, and the equation would then define a set, or locus, of all the points on that line.


 

3) General Form

Let's say A, B, and C are three numbers forming an equation where the same equation can be assumed as:

0 = 2x + 3y + 4


 

All the points with (x, y) coordinates that can make the above statement true forms a line.


 

Using algebra, this general form can be changed into a slope-intercept form, and then you would know the slope and y-intercept for the line.

 

Non-linear Functions:

 

A non-linear function is defined as a polynomial function of two or even higher degree. The linear function is a polynomial function of degree 1. A quadratic function is a polynomial function of degree 2, defined by an equation of the form

y = ax2 + bx + c

The degree of a polynomial function is the degree of the polynomial itself.

For example:

Let us find the degree of the following function and also the points where x and y intercepts.

y= x2-2x-3

The degree of the given equation is 2. To find the point where its graph cuts the x axis, we can make y = 0. now we get,

x2-2x-3 = 0

Solving the equation we get x = 3 and x = -1. These are points where the function graph intercepts the x-axis.
To find the point where the graph intercepts the y-axis, assume x = 0. Now we get y = -3.

 


 

Linear Equations:

 

A linear equation appears like any other form of equation. A linear equation is made up of two expressions sets that are equal to each other. A linear equation is different as, it can have one or even two variables.

No variable in a linear equation is raised to a power greater than 1 or used as the denominator of a fraction. Linear equations graph as straight lines.

A linear equation in two variables shows an experiment between two variables in which the value of one of the variables depends on the value of the other variable. In a linear equation in x and y, x is called an independent variable and y depends on it. We call y the dependent variable. If the variables have other names, yet do have a dependent relationship. The independent variable is plotted along the horizontal axis. Most linear equations are functions (that is, for every value of x, there is only one corresponding value of y). When you assign a value to the independent variable, x, you can compute the value of the dependent variable, y. You can then plot the points named by each (x,y) pair on a coordinate grid.

 

Lines with the Same Slope

Lines with the same slope are either the same line, or parallel lines.

 

Consider 2x + y – 6 = 0. This equation is not in slope-intercept form. There are two ways to put it in slope-intercept form.

1. The actual equation is 2x + y – 6= 0

Subtract y from each side. 2x + y – y – 6 = 0 – y

2x – 6 = 0 – y

Multiply each side by 1.

 

1(2x – 6)= 1(y)

2x + 6 = y

 

  1. Show the original equation. 2x + y – 6 = 0

Add 6 to each side. 2x + y – 6 + 6= 0 + 6

2x + y = 6

Subtract 2x from each side. 2x – 2x + y = 6 – 2x

y = 6 – 2x

The given two equations, 2x + 6 = y and y = 6 – 2x are equal because you can change one equation into the other by using the symmetric property of equality, which states that if a = b, then b = a and the commutative property, which states that a + b = b + a.

commutative property 2x + 6 = y 6 – 2x = y

symmetric property 6 – 2x = y y = 6 – 2x

 

Nonlinear Equations:

Equation whose graph does not form a straight line (linear) is called a Nonlinear Equation. In a nonlinear equation, the variables are either of degree greater than 1 or less than 1, but never 1.

For example:

7x5+ y = 0 and x3+ 13x2-4xy2 = 0 are the examples of nonlinear equations. We can also consider that the form x1/3 + y1/3 = 0 is a nonlinear equation.

Lets take an example of an equation:
(x+ 2)2= 6

This is a non-linear equation because, as per the definition, an algebraic equation is said to be linear if the variable or variables in the equation are of first degree.
Considering the equation (x+ 2)2 = 6

We can see that x can be concluded as x raised to the power 2 or x2.
Therefore, (x+ 2)2= 6 is not a linear equation.

Linear inequalities:

Phenomena of linear inequalities is a set of linear inequalities that anyone comes across all in the same time. Normally, a person starts with two or three linear inequalities.

 

For example:

  • Solve the following system:

    2x– 3y < 12
    x + 5y < 20
    x > 0

    It is better to solve a large number of linear inequalities for "y" on one side. Solving the first two inequalities, get the rearranged system as:

    y > ( 2/3 )x – 4
    y < ( – 1/5 )x + 4
    x > 0

Nonlinear Inequalities:

To solve non linear inequalities, We can use the following steps the following steps:

1.Place every component on the left hand side so that we have for example equation is greater than (>) 0.

2.Factorize and set equal to zero.

3.Solve and put the answers on the number line. Doing so it will divide the number line into two or three parts.

4.Select the value of each part and analyze them for each region and put that acquired value into each of the factors. Put '+' or '-' over the region looking into the values decide positive or negative values.

5.If the region has two '+' or two '-' then the region is positive. If the region has one of each then the region is negative.

6.If the inequality is "<" then include the negative regions.

7.If the inequality is ">" then include the positive regions.

8.If the inequality is a less than or greater than or equal to then include the endpoints with solid dot and the interval []

9.If the inequality is a less (greater) than then do not include the endpoints by showing an open dot and the interval () Lets take an example, Solve x2 + 3x > -2 1.x2 + 3x + 2 > 0 2.(x + 2)(x + 1) = 0 3.x = -2 or x = -

1 This divides the number line into three regions.

4.For the left region we choose-5 and have, -5 + 2 < 0, -5 + 1 < 0 5.For the middle region we choose -1.5, and get, -1.5 + 2 > 0, -1.5 + 1 < 0 For the left region we choose 0 and get, 0 + 2 >0, 0+ 1 >0 6.

The left and right regions are positive and the middle region is negative. 7.The inequality acquired is a greater in quantity we have the solution: (-,-2) U (-1,)