## Precalculus (6th Edition) Blitzer

A function is even when it is symmetric about the $y\text{-}$ axis. A function is odd when it is symmetric about the origin. A function that is not symmetric about the origin or the $y\text{-}$ axis is neither an even function nor an odd function. The graph is clearly symmetrical about the origin; hence, the function $f\left( x \right)$ is an odd function. Hence, the function is an odd function.