Find the center of mass of the planar lamina that is bounded by the graphs of y = x , y=0, and x=2 and whose density is given by the function ρ(x,y)=kxy.

31. Find the area of the surface of z =1+4x^3/2 above the rectangle in the xy plane whose verticesare (0,0), (0,3), (2,0) and (2,3).