Average Values of Functions...?

Hello!

I was absent for a week at school because I got sick, so I'm totally lost! The test is on Tuesday and I was trying to study by myself. Here are some examples of the problems:

1. Find the average value of the function $\displaystyle u(v)=4cosv$ on the interval $\displaystyle [0,\frac{\pi}{2}]$

2. Find the average value of the function $\displaystyle y(v)=(9v)sin(v^2)$ on the interval $\displaystyle [0,\sqrt{\pi}]$

Is is, by any chance, the simple integral of the functions? ANY help is appreciated!