# Math Help - Rates over interval

1. ## Rates over interval

I was going over my test from the beginning of cal 1 and I realized I got a question wrong about rates of change, try to work it out again but couldn't get the answer right. Can anyone show me the right formula to use and how to apply.

Question was cos x over the interval [pi/6, pie/2]

2. Originally Posted by goldenroll
I was going over my test from the beginning of cal 1 and I realized I got a question wrong about rates of change, try to work it out again but couldn't get the answer right. Can anyone show me the right formula to use and how to apply.

Question was cos x over the interval [pi/6, pie/2]
The average rate of change of a function $f$ over an interval $(a,b)$ is given by

$\frac{f(b)-f(a)}{b-a}$

$\frac{\cos\frac{\pi}{2}-\cos\frac{\pi}{6}}{\frac{\pi}{2}-\frac{\pi}{6}}$