Hi, I want to know how to calculate these two lines? Please show me the calculating process.Thank you! The answer in textbook is incorrect.

First line should show: MP = da/dL = (1/2)K1/2L-1/2 Second line should show: MP' = d(MP)/dL = -(1/4)K1/2L-3/2 As K and L are >0, MP' is always negative, showing diminishing returns to labour.Example. Shirley owns a hairdressing salon and employs a number of hairdressers. The number of haircuts she can produce in one day is given by the production function q = KmLm, where Y is the number of haircuts, L is the quantity of labour and K is the amount of capital employed. Differentiating the production function with respect to L gives Market fundamentals which is the marginal product of labour. Differentiating the marginal product gives which tells us that the marginal product of labour is diminishing or, in other words, there are diminishing returns to labour