Please help

In this problem, use the general expressions for left and right sums, left-hand sum = f(to) At + f(t1) At + . . . + f(tn-1)At and right-hand sum = f(t1) At + f(t2) At + . . . + f(tn) At, and the following table: t 0 6 12 18 24 f(t) 20 17 15 11 8 A. If we use n = 4 subdivisions, fill in the values: At = to ; t1 =;t2 = t3 ; t4 f(to) = ;f(t1) =;f(t2) f (t3) = ;f(t4) = B. Find the left and right sums using n = 4 left sum = right sum = C. If we use n = 2 subdivisions, fill in the values: At = to . = t2 f (to) = ;f (t1) =;f(t2) =0 D. Find the left and right sums using n = 2 left sum = right sum =