# Finding a coterminal angle to $(13\pi)/7$ between 0 and $2\pi$

I need to find a coterminal angle to $(13\pi)/7$ between $0$ and $2\pi$.

I'm not sure how to approach this problem as adding $2\pi$ would put me over the domain and subtracting $2\pi$ would put me under. I am told that this is solvable though.

A terminal side determines a unique angle in $[0,2\pi)$ in standard position; the only angle coterminal to $13\pi/7$ that lies in $[0,2\pi)$ is $13\pi/7$ itself. –  Arturo Magidin Sep 17 '11 at 20:18
How about $\frac{13\pi}{7}$ (if equal angles are coterminal) ?