Mark M. answered 01/11/24
Retired math prof. Calc 1, 2 and AP Calculus tutoring experience.
f(x) = x2 - x + 1
Divide the interval [-3,5] into 4 intervals each of width Δx = (5 - (-3)) / 4 = 2
First interval: [-3, -1] with midpoint -2
Second interval: [-1, 1] with midpoint 0
Third interval: [1, 3} with midpoint 2
Fourth interval: [3, 5] with midpoint 4
Midpoint Riemann Sum = f(-2)Δx + f(0)Δx + f(2)Δx + f(4)Δx = 2[7 + 1 + 3 + 13] = 48