(a) Use the definition given below with right endpoints to express the area under the curve y = x3 from 0 to 1 as a limit. The area A of the region S that is bounded above by the graph of a continuous function y = f(x), below by the x-axis, and on the sides by the lines x = a and x = b is the limit of the sum of the areas of approximating rectangles. n A = Jim\" Rn = \"\"31, f(x1)AX + f(x2)AX + --- + f(xn)Ax] = nlewZxl-MX i=1 3 n i l' \"1",. _ (b) Use the following formula for the sum of cubes of the first n integers to evaluate the limit in part (a). 2 13+23+33+~~+n3=[7"(\"2+1)]