## Precalculus (6th Edition) Blitzer

A function is said to be even if is symmetric about the $y\text{-}$ axis. A function is said to be odd function if 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. From the above graph it is clearly symmetrical about the $y\text{-}$ axis; hence, the function $f\left( x \right)$ is an even function. Hence, the function is an even function.