For the production function F (K, L) = √ KL the marginal product of labor is:
MPL=1/2(K/L)^1/2
and the marginal product of capital is:
MPK=1/2(K/L)^1/2
Suppose that a firm with this production function uses 9 units of capital and 4 units of labor. Show that this production function demonstrates a diminishing marginal product of labor.