10 3i 2.12 The sum + was used to estimate the net (signed) area under a i= 10 10 function f from x = a to x = b. a) Assuming a right sum was used, find the values of a and b, and a formula for f(x). b ) Assuming a left sum was used, find the values of a and b, and a formula for f(x). C) Assuming a midpoint sum was used, find the values of a and b, and a formula for f(x)