Good day

Please assist with the following question

Assume a firm produces televisions according to = ( 4) 2 + 20

a) Plot this total product curve for L>0.

b) For which values of L is the marginal product function equal to zero?

c) Graph this marginal product function for all L>0.

d) Assuming the marginal cost of production is constant, what does this suggest about the shape of the marginal cost curve?

Thank You