# Math Help - Periodic Functions

1. ## Periodic Functions

The function f with domain R (all real numbers) is defined by f(x) = e^[cos(x)]. Prove that f is periodic and state its period.

I've always had trouble with graphs. Could someone please explain to me how this particular type of question works again?

Thanxx!

2. Originally Posted by xwrathbringerx
The function f with domain R (all real numbers) is defined by f(x) = e^[cos(x)]. Prove that f is periodic and state its period.
Did you graph this function?
The function has a maximum of $e$ and a minimum of $\frac{1}{e}$.
Now what values of $\cos(x)$ make that happen?
In what range?