Hello all,

My summer school classes just started this week, and unfortunately, math tutoring just so happens to be at the same time as my second class, so I can't get any help from the tutors.

Anyway, I am having problems grasping the Midpoint Riemann problem we have for homework:

Estimate the area under the graph of from to using subintervals of equal length and taking the sample points to be midpoints.

The midpoint Riemann sum ?

The answer I came up with was this:

This is wrong, and I kinda understand why it's wrong, if x started at 0 this would be right, but because it starts at 5, the f(x) should be different numbers (if that makes sense), my problem is not knowing the proper calculations to figure that out.

In my book the formula is this:

Which is extremely confusing to me.

Please help with this problem. Thank You