Thursday, November 18, 2010

degrees and polynomials

A polynomial equation is an equation that can be written in the form

axn + bxn-1 + . . . + rx + s = 0,
where a, b, . . . , r and s are constants.
We call the largest exponent of x appearing in a non-zero term of a polynomial the degree of that polynomial.


Examples
1. 3x + 1 = 0 has degree 1, since the largest power of x that occurs is x = x1. Degree 1 equations are called linear equations.
2. x2 - x - 1 = 0 has degree 2, since the largest power of x that occurs is x2. Degree 2 equations are also called quadratic equations, or just quadratics.
3. x3 = 2x2 + 1 is a degree 3 polynomial (or cubic) in disguise. It can be rewritten as x3 - 2x2 - 1 = 0, which is in the standard form for a degree 3 equation.
4. x4 - x = 0 has degree 4. It is called a quartic.

The polynomials name is depend on their degree of exponents. There many names of in the polynomials. The names are following below:
Name 1: Degree 0- constant.
Name 2: Degree 1- linear.
Name 3: Degree 2 – quadratic.
Name 4: Degree 3 – cubic.
Name 5: Degree 4 – quadratic.
Name 6: Degree 5- quintic.
Name 7: Degree 6 –sex-tic.
Name 8: Degree 7 - degree with number terms.

Linear Equations: 


y= mx+b 
1 degree
0 turns 

When m is Positive: 
 Rises to the Right, Falls to the left. 

  • domain → +∞, range → +∞ (rises on the right)
  • domain → -∞, range → -∞ (falls on the left)





When m is Negative 
Rises to the Left, Falls to the Right 

  • domain → -∞, range → +∞ (rises on the left)
  • domain → +∞, range → -∞ (falls on the right)









Quadratic Equations (parabolic equation)
y=ax² 
2 degree 
1 turn
(a+b)(c+d)
            
When a is Positive 
Rises Left, Rises Right

  • domain → +∞, range → +∞ (rises on the right)
  • domain → -∞, range → -∞ (falls on the left)
When a is Negative 
Falls to the Left, Falls to the right. 

  • domain → +∞, range → -∞ (falls on the right)
  • domain → -∞, range → -∞ (falls on the left)

Naming Polynomials: 
--Number of turns is always 1 less than the degree

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