A Cobb-Douglas production function is given by Q = 5L^1/2 K^1/2. Assuming that capital, K, is fixed at 100, write down a formula for Q in terms of L only. Calculate the marginal product of labour when (a) L = 1 (b) L = 9 (c) L = 10 000. Verify that the law of diminishing marginal productivity holds in this case.