2 x The rectangles in the graph below illustrate a left endpoint Riemann sum for at) : g on the interval [2, 6]. The value of this left endpoint Riemann sum is | , and this Riemann sum is an underestimate of v the area of the region enclosed by y : f(:c), the xaxis, and the vertical lines x = 2 and x = 6. Left endpoint Riemann sum for y : %2 on [2, 6]