The graph of a function f defined on an interval [a, b] is given. (5, 4) y = f(x) (6, 3) 2 (3, 2) a -2 (1, 1) (-1, -1). (0, 0) 2 b -2 (-4, -3) (a) Using the Riemann sums, approximate Sa f (x) dx by choosing u; as the left endpoint of each subinterval. Solve by partitioning the interval [a, b] into subintervals [-4, -1], [-1, 0], [0, 1], [1, 3], [3, 5], [5, 6]. / f ( x)dx ~ (b) Using the Riemann sums, approximate fa f (x) dx by choosing u; as the right endpoint of each subinterval. Solve by partitioning the interval [a, b] into subintervals [-4, -1], [-1, 0], [0, 1], [1, 3], [3, 5], [5, 6]. [ s ( )dx =