# Left and right endpoints

• April 19th 2013, 02:57 PM
dangbeau
Left and right endpoints
Use left and right endpoints and the given number of rectangles to find two approximations of the area of the region between the graph of the function and the x-axis over the given interval.
f(x) = cos(x), (0, $\frac{\pi}{2}$), 4 rectangles

Plese check for me where I'm wrong
the width of each retangles is $\frac{\pi}{8}$

use right endpoints we have

$\sum_{i=1}^4 cos\frac{\pi}{8}i\frac{\pi}{8}$

use left endpoints we have

$\sum_{i=1}^4 cos\frac{\pi}{8}(i-1)\frac{\pi}{8}$
• April 19th 2013, 10:44 PM
chiro
Re: Left and right endpoints
Hey dangbeau.

If what I think you are doing is right, then what you have done is good.