Please give a step by step answer, dont include already existing answers in web, Please include your own work.

4. (a) [8 marks] Find the length of the curve y = - cosh(2x) from point (x, y) = (0, to (x, y) = 1, - cosh 2 ). 2 d Hint: cosh(ax)-sinh(ax) = 1, d d.x (cosh(ax)) = a sinh(ax), d.r (sinh(ax)) = a cosh(ax). (b) [8 marks] Sketch the region of integration and evaluate the repeated integral (2x + y) dady J 2y+1 (c) [6 marks] Reverse the order of integration in the repeated integral in item (b), identify the new integration limits but do not re-evaluate the integral