1 need some help with this question

Problem. 1 : Find an approximation of the area of the region R under the graph of f by computing the Riemann sum of f corresponding to the partition of the interval into the subintervals shown in the figure. Use the midpoints of the subintervals as the representative points. (Round your answer to two decimal places.) 2.0 y= f (x ) 0.8 2 W . Problem. 2: Let f(x) =5 -2x and let R be the area under the graph of f on the interval [0, 2]. (a) Use geometry to find the area of R. ? (b) Use a Riemann sum with five subintervals of equal length (n = 5) to approximate the area of R. Choose the representative points to be the right endpoints of the subintervals. (c) Repeat part (b) with ten subintervals of equal length (n = 10). ? Problem. 3 : Find an approximation of the area of the region R under the graph of the function 16-x2 on the interval [-2, 1]. Use n = 5 subintervals. Choose the representative points to be the left endpoints of the subintervals