question 13. please explain step by step, so that I can apply it to future problems. Thank you.

Let In denote the left-endpoint sum using n subintervals and let Rn denote the corresponding right-endpoint sum. In the following exercises, compute the indicated left and right sums for the given functions on the indicated interval. 12. La for f (x) = 7 , on [2, 3] 13. R4 for g (x ) = cos ( Tra ) on (0, 1]