Please help with explanation!

(A) Estimate the area under the graph of x) = 4.13 + 6 from a: = 1 to z = 3, first using 4 approximating rectangles and right endpoints, and then improving your estimate using 8 approximating rectangles and right endpoints. 4 Rectangles = E] 8 Reotangles = C] (B) Repeat part {A} using left endpoints. 4 Rectangles = [j 8 Rectangles = [j {(3) Repeat part (A) using midpoints. 4 Rectangles = [j 8 Rectangles = E] Consider the integral (3x' + 2x + 4) dx 3 (a) Find the Riemann sum for this integral using right endpoints and n = 3. R3 = (b) Find the Riemann sum for this same integral, using left endpoints and n = 3. L3 =