Verify green's theorem for the disc d with center (0, 0) and radius r and the following functions. (a) p(x, y) = 2xy2, q(x, y) = −2yx2 ∂d p dx + q dy = d ∂q ∂x − ∂p ∂y dx dy = (b) p(x, y) = x + y, q(x, y) = 5y ∂d p dx + q dy = d ∂q ∂x − ∂p ∂y dx dy = (c) p(x, y) = 2xy = q(x, y) ∂d p dx + q dy = d ∂q ∂x − ∂p ∂y dx dy = (d) p(x, y) = 5y, q(x, y) = x ∂d p dx + q dy = d ∂q ∂x − ∂p ∂y dx dy =