Approximate the area of the region bounded Ay f(t ) = cos(t/ 2- 1/8) + by the graph of f(t) = cos (t/ 2-It / 8) and the t-axis on [0,x] with n = 4 subintervals. Use the midpoint of each subinterval to determine the height of each rectangle (see figure). ..... The approximate area of the region is (Round to two decimal places as needed.)