2. Polynomial function
A function P is called a polynomial if
( )
12 1 2 10
nn nn P x a x a x a x ax a
−
− = + ++ + +
where n is a nonnegative integer and the numbers
01,, ,n
aa a are constants called the
coefficients of the polynomial.
˗ The domain of any polynomial is .
˗ If the leading coefficient 0,
n
a ≠ then the degree of the polynomial is n.
˗ A polynomial of degree 1 is of the form ( ) P x mx b = + and so it is a linear function.
˗ A polynomial of degree 2 is of the form ( )
2
P x ax bx c = ++ and is called a
quadratic function. Its graph is always a parabola.
˗ A polynomial of degree 3 is of the form ( )
32 P x ax bx cx d = + ++ and is called a
cubic function.