8. A thin lamina has the shape of a triangle with vertices at (0,0), (2,0), and (2,4). The density function associated with the lamina has equation ρ(x, y )=4x+2y+2 . Find the mass and center of mass of the lamina.

3. A solid E lies within the cylinderx2+ y2 =1, below the plane z = 4 , and above the paraboloid z=1 − x2y2 . The density at any point is proportional to its distance from the axis of the cylinder. Find the mass of E.