Polynomial Functions and Their Graphs

Notes:

Terms

Polynomial function(s): a polynomial function of degree n is a function of the form…
P(x) = a(n)x(n) + a(n-1)x(n-1) + … + a1x + a0
where n is a nonnegative integer and an =/= 0

Leading Term: of a polynomial is the term with the highest exponent.

Zeros of a polynomial: P(x) are numbers c, such that P© = 0 - “x coordinates of the x-intercepts.”

The end behavior of a polynomial: For the graph of any polynomial function, the ends will either point up or down. For example:

As x -> ∞; f(x) (will either) -> ∞ OR -∞
As x -> -∞; f(x) (will either) -> ∞ OR -∞

Odd Degree & Positive Leading Coefficient: Left down & Right up.

Even Degree & Positive Leading Coefficient: Both ends up.

Odd Degree & Negative Leading Coefficient: Left up & Right Down.

Even Degree & Negative Leading Coefficient: Both ends down.


Other Things To Remember:

  • The numbers a0, a1, a2, …, a(n)
    are called coefficients of the Polynomial.

  • a0 is the constant coefficient or constant term.

  • The number a(n), the coefficient of the highest power, is the leading coefficient, and the term a(x)x(n) is the leading term.

Names of certain degrees

  • If a polynomial consists of just a single term, then it’s called a monomial. For example:
    P(x) = x3 and Q(x) = -6x5 are monomials.

  • f(x) = a(1)x +/- a0 is considered a “Linear” equation.

  • f(x) = a(2)x2 +/- a(1)x +/- a0 is considered a “Quadratic” equation.

  • f(x) = a(3)x3 + a(2)x2 + a(1)x + a0 is considered a “Cubic” equation.

Exponents affect the graph!

Even exponent: - Parabola - Bigger exponent means flatter base (near zero)(?) Odd exponent: - Zig-Zag(?) - Bigger exponent means flatter base (near zero)(?)