A3, M3. (a) Set up a definite integral that describes the length of the curve y = x3 + x between the points (-1, -2) and (1, 2). (b) Write down an expression for your definite integral from part (a) as a limit of finite sums. A5, M5, M6. A rod with uniform density (mass/unit length) p(x) = x3 sin(x2) lies on the x-axis between x = 0 and x = 3/2. Find the total mass of the rod