Approximate 15 In(x) dx 3 using each of the following Riemann sums with 4 subintervals of equal length. Do not simplify your answer. (a) Left Riemann Sum = 15 In (15 ) - 3 In(3) - 12 X (b) Right Riemann Sum = (c) Midpoint Rule = 15 In(15) - 3 In(3) - 12 X