## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

$\text{Not a polynomial function because it has a term with a negative exponent/power.}$
$\text{A polynomial function is a function of the form}$ $$f(x)=a_n x^n +a_{n-1} x^{n-1}+...+a_1 x+ a_0$$ Where the coefficients $(a_n, a_{n-1}.....)$ are real numbers and $n$ is a non-negative integer $f \text{ can be rewritten as: }$ $$f(x)=1-x^{-1}$$ Since the term $x^{-1}$ has a negative power, the function isn't a polynomial.