Let Ly denote the left-endpoint sum using n subintervals and let R, 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) = _on [2, 3] 13 . R4 for g (x) = cos (xx) on [0, 1] 14 . Le for f (x) = _ on [2, 5] 15 . R6 for f (x) = 1 x (x- 1) on [2, 5] 16 . R4 for - x2+1 1 on [-2, 2] 17 . LA for - x 2 +1 on [-2, 2] 18 . R4 for x2 - 2x + 1 on [0, 2]