CPM Homework Help : PC3 Problem 8-31

What is the average rate of change for the following functions over the given intervals?

$f(x)=\sin(x)$ $\frac{\pi}{2}\le x\le\pi$
Step (a):
$\frac{\sin(\pi) - \sin\left(\frac{\pi}{2}\right)}{\pi - \frac{\pi}{2}} = ?$

$f(x)=\log(x)$ $1\le x\le10$
Step (b):
$\frac{f(10) - f(1)}{10 - 1} = ?$
Hint (b):
$\log(1)=0$