Monday, October 1, 2012

Rounding Decimals to the Nearest Hundredth

Introduction to rounding decimals to the nearest hundredth:

Rounding decimals to the nearest hundredth concerns mainly about how to round the decimals to two decimal places. Certain sums involve the remainder that the decimal values after the decimal point grow to infinity. Here our aim is to shorten our result of decimal values to nearest hundredth, for those rounding decimals to the nearest hundredth, certain rules are to be followed. Let us see problems for rounding decimals to the nearest hundredth.

Rounding Decimals to the Nearest Hundredth:

To round the values to nearest hundredth, we follow 2 rules to remember:

Rule One: Find what is our rounding digit is given for and here the rounding decimals to the nearest hundredth s, so see the right side of after the two decimal places. If that digit after 2 decimal places if less than 5, simply remove all the digits to the right of nearest hundredth decimal place.

Rule Two:   Find what is our rounding digit is given for and here the Rounding decimals to the nearest hundredth s, so see the right side of two decimal places. If that digit is 5 or greater than 5, add one to the rounding digit at nearest hundredth decimal place and drop all digits to the right of nearest hundredth decimal place.

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Rounding Decimals to the Nearest Hundredth:

Example 1:

Consider our answer is 11.884721952 but we are asked to give a shorter answer –rounding decimals to the nearest hundredth . At the moment our answer has 9 figures following the decimal point.

Our ‘cut-off point’ comes after the ‘8’ 11.88 | 4721952

this number is greater than 11.88, but lower than 11.89. Look at which is it closer to?

See the 3rd number after the decimal point, that is the number after that ‘cut-off point’.

If the number is 0,1,2,3, or 4 round DOWN to 11.88

If the number is 5,6,7,8, or 9 round UP to the next number 11.89.

Ans:   11.88 to two decimal places.

Example 2:

Consider our answer is 19.367721 but we are asked to give a shorter answer –rounding decimals to the nearest hundredth . At the moment our answer has 6 figures following the decimal point.

Our ‘cut-off point’ comes after the ‘6’ 19.36 | 7721

this number is greater than 19.36, but lower than 19.37. Look at which is it closer to?

See the 3rd number after the decimal point, that is the number after that ‘cut-off point’.

If the number is 0,1,2,3, or 4 round DOWN to 19.36

If the number is 5,6,7,8, or 9 round UP to the next number 19.37.

Ans:   19.37 to 2 decimal places.

Wednesday, September 26, 2012

Practice Algebra Notes

Introduction :

Algebra is the most important branch of the mathematics concerning the study of the rules of operations and relations, and the constructions and concepts arising from them, including terms, polynomials, equations and algebraic structures. Together with the geometry and analysis, topology, combinatorics, and number theory, algebra is one of the main branches of pure mathematics. And now let us see about the practice algebra notes (source in Wikipedia)


Practice Algebraic Notes:

Practice Notes for Variable:

A term or measure, which takes as the unusual numerical values, is called a variable. Generally we represent the variables and have some letters, says x, y, z, etc.

Finding the value of an Expression:

The method of replacing the variables by numerical values are called substitution. So the value of an expression depends on the value of its variables.

Practice algebra notes for Algebraic Equation:

An algebraic equation is the report given of equality, which contains unknown quantities or variables.

Practice algebra notes for Simple equation:

An equation, which has only one variable whose power is one, is called a simple equation

Example Algebraic Problem in Practice Algebra Notes:
Ex 1:

This problem illustrates that the correct use of the distributive property.

Solve 3× (x + 6 + 9) = 66.

Sol:

•    Grouping like terms, the left side of the equation becomes

3 × (x + 6 + 9) `=>` 3 × (x + 15)

•    Using the distributive property,

3 × (x + 15) `=>` 3 × x + 3 × 15

•    Carrying out multiplications,

3 × x + 3 × 15  `=>` to 3x + 45

•    The equation now becomes

3 x + 45 = 66.

•    Subtracting a 45 (adding a -45) to each side gives us

3x + 45 + (-45) = 66 + (-45)

3x + (45 + (-45)) = 66 - 45

3x + 0 = 21

3x = 21

•    Since the x is multiplied by 3, we divide both sides by 3 to solve for x:

3x = 21

3x ÷ 3 = 21 ÷ 3

(3x)/3 = 7

x = 7.

We get the answer value is X = 7

•    We can check this answer in solution of the original equation:

3 × (7 + 6 + 9) = 66

3 × 22 = 66

66 = 66 so our answer is correct.

Practice Algebra Notes Problem:

Solve 3× (X + 3 + 6) = 54.

Answer: 9

Solve 4× (X + 5 + 7) = 60.

Answer: 3

Friday, September 21, 2012

Practice Counting Numbers

Practice counting Numbers:

A number is a numerical thing, which is used for calculating and counting. It is also referred as numeral and involves zero, negative numbers, rational numbers, irrational numbers, etc,.

The procedure of numerical function involves one or more numerical as income and generate its relevant numerical outcome. This function includes arithmetic operation such as addition, subtraction, multiplication, division, and exponentiation.

The numbers are classified as follows,

Natural numbers
Integers
Rational numbers
Real numbers
Complex numbers
Computable numbers
Prime number

Examples for Practice Counting Numbers:
Counting number is a positive number with countable of one, two, three, and so on. Sometimes it contains the integer zero (0) in the table of that counting numbers. So, it is also referred to as Natural number. The sign of natural number is ‘N’. Some case it is called as skip count because of each count must be done by skipping.

General Rules:

Counting numbers include some general rules. Let take ‘B’ is counting number then it follows

Add ‘B’ to the earlier number
Skipping and counting each further number by ‘B’.
Note: Here ‘B’ may be a number or symbol or object

Practice Counting Problems:

1solve the practice problem) Counting downwards from number 13 to 2 with numbers:

Solution:

Starting from 13 to 2

N = ( 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2)

solve the practice problem2) How many heart symbols are there in following set (♥, ♥, ♥, ♥)

Solution:

There are 4 heart symbols in the set

solve the pratice problem 3) Counting the number from 18 to 42 by 6’s

Solution:

Thus, the count by 6’s may be adding number 6 to the earlier number (Rule1)

So Start from 18= 18+6, 18+6+6.

N = (18,24, 30, 36, 42)

4) How many square numbers are there in 100

Solution:

Square numbers in 100 = (1, 4, 9, 16, 25, 36, 49, 64, 81, 100)

Therefore, total square numbers are 10 in the given set.

5) How many club suits are there in following set (♣, ♣, ♣, ♣, ♣)

Solution:

There are 5 club suit in given set

6) How many six letter words are there in the following set (tennis, ball, four, pen, hundred, street, head, man)

Solution:

Six letter words are tennis, street. Therefore, there are 2 six letter words.

Wednesday, September 12, 2012

Inverse Operations Addition and Subtraction

Introduction :

The addition is the basic process in arithmetic’s. The addition   process is to add the two numbers and give the combination of that number. Summation the arithmetic process of summing calculating the sum of two or more numbers. A part that is added to something to improve it; the subtraction process is inverse of the addition A component that is subtracted to something to reduce it.


Explanation of Inverse Operations Addition and Subtraction

Addition:

The addition process is the main function in the arithmetic. The simple and effective process. Every function is based on the addition.

We will learn the addition process in simple way.

Here will explain the concepts.

Ex:

The two apple is added to four apple finally what will be the out put of the problem.

Sol:

Step1: First, add   two apples to four apples.

Step2: 2 + 4

Step3: the final out put 6. The output will changed for the reason combination of two quantities.

\Subtraction:

The subtraction is the inverse of the addition process. This process is reducing the total quantities.

We will learn the basic process of subtraction method.

Ex:

The six apples in the one bag. Ram already took two apples in the bag. What will be the remaining apples in the bag?

Sol:

The subtraction method is opposite of the addition process. This process reduce the total quantities,

Step1: the total quantities are 6 apples.

Step2: the ram took apples are 2

Step3: So, total apples – ram took apples= final quantities

Step4:6-2=4. Final apples are 4.

Practice Problems on Inverse Operations Addition and Subtraction

Ex:1 Ravi had 3 oranges and raja have 4 apples and 2 oranges. What are the total apples and oranges both have solve this problem?

Sol: 5 oranges and 4 apples

Ex:2 Ravi had 4 pens and 3 books, raja have 4 pencil and 2books. What are the total books, pens and pencil both have solved this problem?

Sol :5 books,4 pens,4 pencils

Sunday, September 9, 2012

Factoring Fractional Exponents

Introduction to factoring:

In mathematics, a rational function is any function which can be written as the ratio of two polynomial functions. Factorization (also factorization in British English) or factoring is the decomposition of an object (for example, a number, a polynomial, or a matrix) into a product of other objects, or factors, which when multiplied together give the original.

Example Problems for Factoring Fractional Exponents

Factoring fractional exponents example problem 1:

Factoring the given fractional expression `(1 / 3)` x^2 - `(11 / 3)` x - 144 = 0

Solution:

Given fractional expression is `(1 / 3)` x^2 - `(11 / 3)` x - 144 = 0

Multiply the given expression by 3 on both the sides, we get

x^2 - 11x - 432 = 0

Factorize the above equation, we get

x^2 - 27x + 16x - 432 = 0

Grouping the first two terms and second terms, we get

(x^2 - 27x) + (16x - 432) = 0

Take common terms, we get

x (x - 27) + 16 (x - 27) = 0

(x - 27) (x + 16) = 0

The factors of the given fractional expression is (x - 27) and (x + 16)

Answer:

The final answer is (x - 27) and (x + 16)

Factoring fractional exponents example problem 2:

Factoring the given fractional expression `(1 / 5)` x^2 - `(27 / 5)` x - 74 = 0

Solution:

Given fractional expression is `(1 / 5)` x^2 - `(27 / 5)`x - 74 = 0

Multiply the given expression by 5 on both the sides, we get

x^2 - 27x - 370 = 0

Factorize the above equation, we get

x^2 - 37x + 10x - 370 = 0

Grouping the first two terms and second terms, we get

(x^2 - 37x) + (10x - 370) = 0

Take common terms, we get

x (x - 37) + 10 (x - 37) = 0

(x - 37) (x + 10) = 0

The factors of the given fractional expression is (x - 37) and (x + 10)

Answer:

The final answer is (x - 37) and (x + 10)

Factoring fractional exponents example problem 3:

Factoring the given fractional expression `(1 / 7)`x^2 - `(12 / 7)`x + 5 = 0

Solution:

Given fractional expression is `(1 / 7)`x^2 - `(12 / 7)`x + 5 = 0

Multiply the given expression by 7 on both the sides, we get

x^2 - 12x + 35 = 0

Factorize the above equation, we get

x^2 - 7x - 5x + 35 = 0

Grouping the first two terms and second terms, we get

(x^2 - 7x) - (5x - 35) = 0

Take common terms, we get

x (x - 7) - 5 (x - 7) = 0

(x - 7) (x - 5) = 0

The factors of the given fractional expression is (x - 7) and (x - 5)

Answer:

The final answer is (x - 7) and (x - 5)

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Practice Problems for Factoring Fractional Exponents

Factoring fractional exponents practice problem 1:

Factoring the given fractional expression `(1 / 24)`x^2 + `(23 / 24)`x - 12 = 0

Answer:

The final answer is (x + 32) and (x - 9)

Factoring fractional exponents practice problem 2:

Factoring the given fractional expression `(10 / 7)`x^2 - `(59 / 7)`x + 7 = 0

Answer:

The final answer is (10x - 49) and (10x - 10)

Wednesday, September 5, 2012

Factoring Polynomials by Grouping


Introduction of factoring polynomials by grouping:
  • In general, the sum of a countable number of monomials is referred as a polynomials. The way of writing a polynomials as a product of two or more simpler polynomials is calledfactorization. The process of factorization is also known as the resolution into factors or factoring polynomials. Each simpler polynomial in the product is called a factor of the given polynomial.   
  • Factoring polynomial by grouping method is used for the expressions containing more than three terms.
Factoring Polynomials Using Grouping:

Factoring polynomials by grouping involving four or more than four terms can be grouped using the following steps:

Step 1:  The terms having common factors should be grouped.
Step 2: The Greatest Common Factor (GCF) is taken out.
Step 3:  In the third step, we have to use the distributive law to find the factors.
                                               The distributive law is given by
                                                         a (b + c) = a b + a c

Example Problems on Factoring Polynomials by Grouping:

Ex 1:  Factoring the given polynomial, 3x2 + 9x3 + 7x7 + 21x8, by grouping:     

Sol :   Step 1:  The terms having common factors should be grouped.
                                     (3x2 + 9x3) + (7x7 + 21x8).
Step 2: The Greatest Common Factor (GCF) is taken out.
                            3x2 + 9x3 and 7x7 + 21x8 both can have a GCF.
               Taking out the GCF outside, we get
                         (3x2 + 9x3)+ (7x7 + 21x8) = 3x2 (1 + 3x) + 7x7 (1 + 3x)

Step 3: Use  distributive law to find the factors.
                Note that there is a common factor, 1 + 3x. So, factor out 1+3x.
                  By distributive law, we get
                                3x2 + 9x3 + 7x7 + 21x= (3x2 + 7x7) (1 + 3x).

Ex  2:   Factoring the given polynomial by grouping:  2x3+6x2−6x−18

Sol :   Step 1: The terms having common factors should be grouped.
                                               (2x3+6x2) + (−6x−18)
Step 2: The Greatest Common Factor (GCF) is taken out.
                                  (2x3+6x2) and  (−6x−18) both have a GCF
               Taking out the GCF outside, we get
                                   (2x3+6x2) + (−6x−18) = 2x2(x+3)-6(x+3)
Step 3:  Use distributive law to find the factors.
              Note that there is a common factor, x+3. So, Factor out (x+3).
               By distributive law, we get
                                             2x3+6x2−6x−18=(x +3) (2x2-6).
Ex 3 :  Factoring the given expression by grouping: 2x2 - 3x + 10x - 15.

Sol :  Step 1:  The terms having common factors should be grouped.
                                       (2x2 + 10x) + (- 3x – 15)
Step 2: The Greatest Common Factor (GCF) is taken out.
                            2x2+10x) and  (−3x−15) both have a GCF
              Taking out the GCF outside, we get
                              (2x2+10x) + (−3x−15) = 2x(x+5)-3(x+5)

Step 3:  Use distributive law to find the factors.
              Note that there is a common factor, x+5. So, Factor out (x+5).
               By distributive law,we get
                                             2x2 - 3x + 10x – 15=(x+5) (2x-3).
These are the examples for the factoring polynomials by grouping.

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Sunday, September 2, 2012

Complex Matrix Inverse

Introduction

In algebra, the determinant is a particular number related with some square matrix. The essential geometric significance of a determinant is a scale factor for compute when the matrix is considered as a linear transformation. Thus a 3× 3 matrix with determinant 3 when useful to a place of points with fixed area will convert those points into a place with double the area. Determinants are significant together in calculus, where they go into the replacement rule for various variables, and in multi linear algebra.

`A = [[A,B],[C,D]] If AD - BD != 0` , then A has an inverse, Denoted` A^-1`

`A^-1 = 1/(AD-BC) [[D,-B],[-C,A]]`

Complex Matrix Inverse - Examples:

Complex matrix inverse - Example 1:

Find the Complex inverse matrix of the matrix below?

`A = [[4,2],[3, 8]]`

Solution:

Inverse A =` 1/((8*4)-(3*2)) [[8,-3],[-2,4]]`

= `1/(32-6) [[8,-3],[-2,4]]`

=` 1/26[[8,-3],[-2,4]]`

= `1/26 * [[8,-3],[-2,4]] = [[8/26, -3/26],[-2/26,4/26]]`

= `[[4/13, -3/26], [-1/13, 2/13]]`

Complex matrix inverse - Example 2:

What is the inverse of the matrix below?

`[[9, 1], [6, 3]]`

Solution:

Inverse of the matrix is the

Inverse A =` 1/((9*3)-(6*1)) [[3,-1],[-6,9]]`

= `1/(27-6) [[3,-1],[-6,9]]`

= `1/21[[3,-1],[-6,9]]`

= `1/21 * [[3,-1],[-6,9]] = [[3/21, -1/21],[-6/21,9/21]]`

` [[3/21, -1/21],[-6/21,9/21]] = [[1/7, -1/21],[-2/7,3/7]]`

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Complex matrix inverse - Example 3:

What is the inverse of the matrix below?

A =  ` [[7, 1], [5, 3]]`

Solution:

Inverse of the matrix is the

Inverse A =` 1/((7*3)-(5*1)) [[3,-1],[-5,7]]`

= `1/(21-5) [[3,-1],[-5,7]]`

= `1/16[[3,-1],[-5,7]]`

= `1/16 * [[3,-1],[-5,7]]`

= `[[3/16, -1/16],[-6/16,9/16]]`

`[[3/16, -1/16],[-6/16,9/16]] = [[3/16, -1/16],[-3/8,9/16]]`

Complex Matrix Inverse - more Examples:

Complex matrix inverse - Example 1:

What is the inverse of the matrix below?

` [[8, 2], [6, 4]]`

Solution:

Inverse of the matrix is the

Inverse A = `1/((8*4)-(6*2)) [[4,-2],[-6,8]]`

`= 1/(32-12) [[4,-2],[-6,8]]`

`= 1/20[[4,-2],[-6,8]]`

` = 1/20* [[4,-2],[-6,8]]`

`= [[4/20, -2/20],[-6/20,8/20]]`

`[[4/20, -2/20],[-6/20,8/20]]= [[1/5, -1/10],[-3/10,2/5]]`

Complex matrix inverse - Example 2:

Find the inverse Complex matrix of the matrix below?

`[[9, 3], [7, 5]]`

Solution:

Inverse of the matrix is the

Inverse `A = 1/(9*5)-(7*3) [[5,-3],[-7,9]]`

`= 1/(45-21) [[5,-3],[-7,9]]`

`= 1/24[[5,-3],[-7,9]]`

`= 1/24* [[5,-3],[-7,9]]`

`= [[5/24, -3/24],[-7/24,9/24]]`

`[[5/24, -3/24],[-7/24,9/24]] = [[5/24, -1/8],[-7/24,9/24]]`

Complex matrix inverse - Example 3:

What is the inverse of the matrix below?

`[[10, 4], [8, 6]]`

Solution:

Inverse of the matrix is the

Inverse `A = 1/(10*6)-(8*4) [[6,-4],[-8,10]]`

`= 1/(60-32) [[6,-4],[-8,10]]`

`= 1/28 [[6,-4],[-8,10]]`

`= 1/28* [[6,-4],[-8,10]]`

`= [[6/28, -4/28],[-8/28,10/28]]`

`[[6/28, -4/28],[-8/28,10/28]] = [[3/14, -1/7],[-2/7,5/14]]`