Use the Midpoint Rule with the given value of n to approximate the integral. Round the answer to four decimal places.

integral from o to pi/2 (2cos^3(x))dx ,
n = 4

M4 = ??????

Thanks!!!

1 answer

With 4 divisions, the boundaries are
0 pi/8 pi/4 3pi/8 pi/2
So, the midpoints are at
pi/16,3pi/16,5pi/16,7pi/16

So, we have 4 rectangles with width dx=pi/8, and heights
2cos^3(pi/16),...

Add up the areas of the rectangles. I get 1.3330

To check,

∫[0,pi/2] 2cos^3(x) dx = 4/3 = 1.3333