(a) Estimate the area under the graph of f(x) = 4 + 2x2 from X = 1 to X = 2 using three rectangles and right endpoints. R3 = Then improve your estimate by using six rectangles. R6 = Sketch the curve and the approximating rectangles for R3. \f12 y 12 10 10 8 61 2 2 O- -1 X 1 2 O-1 X 2 12 4 12+ 10 10 8 8 6 2 O-1 X 1 2 O-1 X 2(b) Repeat part (a) using left endpoints. L3 = L6 = Sketch the curve and the approximating rectangles for L3. Y Y 12 12 10 1o 8 8 6 I I A X x -1 1 2 31 1 2 A Y Y 12 12 10 10 8 8 6 6 " \f(d) From your sketches in parts (a)-(c), which appears to be the best estimate? _\\ L6 R6