Question 2: Jul 2021 a) Consider the following sum of iterated integral 2 x 4 4-X f ( x.y) dA = [ [f (x.y) dydx + f (x,y) dydx R 0 0 2 0 Sketch the region R and express the double integrals in reversed order of integration. b) Use polar coordinate to evaluate ( x+y dA, where R is the region in the first quadrant and is bounded between the circle x2 + y? =1 and x2 + y? =4. c) Find the volume of a solid of f ( x, y ) = x +2xy + 3x. The boundaries of the bottom of the solid are y = x , y =0 and x =2