Is #f(x)=(2x^3-5x^5-2)/(9x^2+9)# a polynomials?

1 Answer
Jun 29, 2015

No, the ratio is not a polynomial. (The numerator and denominator separately are polynomials.)

Explanation:

A polynomial (in one variable) consists of terms (things added together), each of which is a constant (a number) times the variable raised to some positive whole number power (or just a constant alone).

#2x^3-5x^5-2# is an example of a polynomial.
The terms are #2x^3# and #-5x^5# and #-2#.
Actually, I've listed the terms with non0zero coefficient. If we want, we can also insert "terms" #0x^4# and #0x^2# and so on. (And even #0x^7# if there is a reason to add that term.)

The expression #(2x^3-5x^5-2)/(9x^2+9)# is called a Rational expression.

(And the function #f(x) = (2x^3-5x^5-2)/(9x^2+9)# is called a Rational Function.)