Chapter 5.1, Problem 6ES

Estimate the area between the graph of the function $f$ and the interval $\left[a,b\right]$ . Use an approximation scheme with $n$ rectangles similar to our treatment of $f\left(x\right)=x^2$ in this section. If your calculating utility will perform automatic summations, estimate the specified area using $n=10,50$ , and $100$ rectangles. Otherwise, estimate this area using $n=2,5$ , and $10$ rectangles.

$f\left(x\right)=\cos x;\left[a,b\right]=\left[-\pi /2,\pi /2\right]$