roblem l3. (12.1/4) a) Estimate the volume of the solid that lies below the surface _ = x + 2 J22 and above the rectangle R = {(x,y) |0 :1 x :1 2 , 0 S y S 4}. Use a Riemann sum with m = n = 2 and choose the sample points to be the lower right corners of each subrectangle. b) Use the Midpoint Rule (use the center of each subrectangle) to estimate the volume in part (a)