الثلاثاء، 21 ديسمبر 2010

About Mathematics

http://www.mathematics-i2.com/About_Mathematics.html


Simple Mathematics


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Polynomials

Polynomials
Polynomials are algebraic expressions that include real numbers and variables. Division and square roots cannot be involved in the variables. The variables can only include addition, subtraction and multiplication.

Polynomials contain more than one term. Polynomials are the sums of monomials.

A monomial has one term: 5y or -8x2 or 3.
A binomial has two terms: -3x2 2, or 9y - 2y2
A trinomial has 3 terms: -3x2 2 3x, or 9y - 2y2 y

The degree of the term is the exponent of the variable: 3x2 has a degree of 2.
When the variable does not have an exponent - always understand that there's a '1' e.g., 1x
Example:
x2 - 7x - 6

(Each part is a term and x2 is referred to as the leading term.)
Term Numerical Coefficient
x2
-7x
-6 1
-7
-6

8x2 3x -2 Polynomial 3
8x-3 7y -2 NOT a Polynomial The exponent is negative.
9x2 8x -2/3 NOT a Polynomial Cannot have division.
7xy Monomial s
Polynomials are usually written in decreasing order of terms. The largest term or the term with the highest exponent in the polynomial is usually written first. The first term in a polynomial is called a leading term. When a term contains an exponent, it tells you the degree of the term.
Here's an example of a three term polynomial:
6x2 - 4xy 2xy - This three term polynomial has a leading term to the second degree. It is called a second degree polynomial and often referred to as a trinomial.
9x5 - 2x 3x4 - 2 - This 4 term polynomial has a leading term to the fifth degree and a term to the fourth degree. It is called a fifth degree polynomial.
3x3 - This is a one term algebraic expression which is actually referred to as a monomial.
One thing you will do when solving polynomials is combine like terms. This is also discussed in lesson 2 - Adding and Subtracting polynomials.
Like terms: 6x 3x - 3x
NOT like terms: 6xy 2x - 4
The first two terms are like and they can be combined:

5x2 2x2 - 3

Thus:

10x4 - 3



Adding Polynomials

To add polynomials, you must clear the parenthesis, combine and add the like terms. In some cases you will need to remember the order of operations. Remember, when adding and subtracting like parts, the variable never changes.
Here are a couple of examples:
(5x + 7y) + (2x - 1y)
= 5x + 7y + 2x - 1y ----- (Clear the parenthesis)
=5x + 2x + 7y - 1y ----- (Combine the like terms)
= 7x + 6y --- (Add like terms)
Another Example:
(y2 - 3y + 6) + (y - 3y 2 + y3)
y2 - 3y + 6+ y - 3y2 + y3 ---- (Clear the parenthesis)
y3 + y2 - 3y2 - 3y + y + 6----- (Combine the like terms)
y3 - 2y2 - 2y + 6---- (Add like terms)
Subtracting Polynomials
To subtract polynomials, you must change the sign of terms being subtracted, clear the parenthesis, and combine the like terms. Here's an example:
(4x2 - 4) - (x2 + 4x - 4)
(4x2 - 4) + (-x2 - 4x + 4) ---- (Change the signs)
4x2 - 4 + -x2 - 4x + 4 ---- (Clear the parenthesis)
4x2 -x2 - 4x- 4 + 4 -- ----- (Combine the like terms)
3x2 - 4x
Another Example:
(5x2 + 2x +1) - ( 3x2 – 4x –2 )
5x2 + 2x +1 - 3x2 + 4x +2 --(Change the signs and clear the parenthesis)
5x2 - 3x2 + 2x+ 4x+1 + 2 --(Combine the like terms)
2x2+ 6x +3
Polynomial Definitions of Terms:
A monomial has one term: 5y or -8x2 or 3.
A binomial has two terms: -3x2 + 2, or 9y - 2y2
A trinomial has 3 terms: -3x2 + 2 +3x, or 9y - 2y2 + y
The degree of the term is the exponent of the variable: 3x2 has a degree of 2.
When the variable does not have an exponent - always understand that there's a '1' e.g., 3x


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