please give answer to the following calculus question with step by step calculation to understand clearly

4. (a) [6 marks] Sketch the region of integration and evaluate the following integral by converting it to polar coordinates 9-2 2 (x2 + y?) dy dx . 3 . Jo X Hint: x = rcos0, y = r sin 0, dxdy -> r dr de. (b) Consider the integral NE 2 sin x dx dy . i. [2 marks] Sketch the region of integration. ii. [2 marks] Reverse the order of integration. iii. [2 marks] Use the expression obtained in item 4(b) ii to evaluate the integral. y zo