need help with all

(a) A friend of yours is working on the following integration question and writes down -+ 2x + 6x + Cas an answer. Without evaluating the integral, explain why your friend is incorrect (c) Evaluate S_, x5 - x3 dx without evaluating the integral (d) Consider the curve with equationy = ex - e-Zx (ii) Find the coordinates of the stationary point and determine its nature. (ili) Discuss the behaviour of the curve as x - too. (iv) Hence sketch the curve in the space provided below O