In: Economics
TC(Q) = 2Q3− 15Q2 + 40Q (total cost function)
MC = dTC/dQ (the first order derivative of the total cost function) = 6Q^2-30Q+40
AC = TC/Q = 2Q^2-15Q+40
long run equilibrium occurs at a point where price equals the minimum of average total cost P=min ATC.
to find min ATC we take first order derivative of average cost function.
dAC/dq = 4Q - 15 = 0 or Q = 15/4 = 3.75 (Quantity for each firm)
at Q = 3.75, ATC = 2*(3.75)^(2)-15*3.75+40 = 11.875
So the long run equilibrium price will be $11.875
If the demand function is given by Q = 999 − 0.25P, then at long run Price P =11.875, Quantity sold will be Q= 999-0.25*11.875 = 996.03
Number of firms = 996.03/3.75 = 265.608