1. (a) Estimate the area under the graph of f(x) = 1 +x from x = =1 to x = 2 using three rectangles and right endpoints. Then improve your estimate by using six rectangles Sketch the curve and the approximationg rectangles.- (b) Repeat part (a) using left endpoints. (c) Repeat part (b) using midpoints. (d) From your sketches in parts (a)-(c) which appears to be the best estimate