1. The problem statement, all variables and given/known data I have to approximate the integral of sin(sqrt(x)) from 0 to 40, with n=4, using the midpoint rule. 2. Relevant equations 3. The attempt at a solution I found delta x to be 10, obviously, since I have to approximate from 0 to 40 using 4 large rectangles. I am having trouble finding f(.5(x(of i-1)+x(of i)))). I don't really even know where to start!