Work Step by Step
If $f$ is an even function, then it must have $y$-axis symmetry, since $f(-x)=f(x)$. In other words, the graph looks the same on the left and right sides of the $y$-axis.
You can help us out by revising, improving and updating this answer.Update this answer
After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.