13 el/x marks 10. Evaluate 2 dx. marks 11. (a) Determine the partial fractions decomposition/expansion and solve for any unknown constants for 2+3x + x2 f(x) = x(x2 + 1) (b) Evaluate the integral / f(x) dr. 8 marks] 12. Sketch the region bounded by the curves y - T - 2x and y = 4 - x2, and then find its area. 5 marks] 13. The region bounded by y = x2 + 1 and y = r + 3 is to be rotated about the r axis. (a) Sketch a diagram illustrating the volume of revolution, including a relevant cross-sectional slice. (b) Write down the area A(r) of a cross section and then an integral that gives the volume of revolution from part (a). (Note: DO NOT spend time evaluating the integral.)