A cost minimizing firm has the following short run production function
Q=f(L,K)=72L + 5L^2 - 0.2L^3
(a) Briefly explain why this is short run production function.
(b) At what level of employment would diminishing returns set in for the variable input?
(c) If the market determined real wage rate is $20 determine the amount of labor a cost minimizong firm would hire in order to minimize the total of production