Approximate the area of the region bounded by the graph of f(t) = cos (t/2- 3n/8) and the t-axis on [0,1] withn= 4 subintervals. Use the midpoint of each subinterval to determine the height of each rectangle (see figure). f(t) = cos(t/2- 31/8) 1- 0.5- 3x 2 The approximate area of the region is (Round to two decimal places as needed.) Evaluate the following integral by completing the square and using a substitution to reduce it to standard form. dx (x+ 1)/x? +. + 2x - 15 dx (x+ 1)Vx? + 2x- 15