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Microeconomic homework 9 Pr P o r b o l b e l m e m 1 : 1 :
a. What is price and optimal quantity that gives the firm maximum profit? Using Lerner
indicator (L) to identify market power of this firm?
➢ Demand function is 𝑃 = 15 − 𝑄 (1) so the marginal revenue function is 𝑀𝑅 = 15 − 2𝑄 (2).
➢ The total cost function is 𝑇𝐶 = 7𝑄 so the marginal cost function is 𝑀𝐶 = 7.
➢ The firm maximum profit when 𝑀𝑅 = 𝑀𝐶 so 15 − 2𝑄 = 7.
➢ Solve the equation we have optimal quantity is 4 units.
➢ Replacing Q in (1) by 4, we have the optimal price is 9 dollars.
➢ Using the Lerner indicator we have market power for this firm is: L = P−MC = 9−7 = 2 P 9 9
b. What is price and optimal quantity for society (for perfect competitive market)? Identify dead-
weight loss (DL) created by this firm?
➢ The price and optimal quantity for society are at the point that D = MC so 15 − Q = 7
➢ Solving the equation, we have optimal quantity for society is 8 units.
➢ Replacing Q in (1) by 8, we have the optimal price for society is 7 dollars. P 9 A B MC 7 E 4 8 Q The d a
e d weight lost is SAEB so 𝐷𝑊𝐿 = (9−7)(8−4) = 4 2 Pr P o r b o l b e l m e m 2 2
a. What is optimal output level that maximizes profit? What is that maximum profit?
Demand function is 𝑃 = 100 − 𝑄 so marginal revenue function is 𝑃 = 100 − 2𝑄.
Total cost function is TC = Q. AVC + FC = Q2 + 4Q + 200 so the marginal cost function is MC = TC' = 2Q + 4.
To maximize profit MR = MC so 100 − 2Q = 2Q + 4.
Solving the equation, we have the optimal quantity for the firm is 27 units.
Replacing Q in demand function we have optimal price for the firm is 73 dollars.
b. What is consumer surplus (CS) and deadweight loss (DL) created by this firm? P MC I P’ A P1 B E D Q’ Q (100 − 73).27
𝐶𝑜𝑛𝑠𝑢𝑚𝑒𝑟 𝑠𝑢𝑟𝑝𝑙𝑢𝑠 = 𝐼𝐴𝑃’ = = 364.5 2 (32 − 27). (73 − 46)
𝐷𝑒𝑎𝑑𝑤𝑒𝑖𝑔ℎ𝑡 𝑙𝑜𝑠𝑠 = 𝐸𝐴𝐵 = = 67.5 2
c. Assume this firm applies perfect price discrimination, what is quantity and variable profit of the firm?
If the firm applies perfect price discrimination, we have optimal quantity at 𝑀C = D so optimal quantity
is 32 units and optimal price is 68 dollars.
Variable profit for the firm is producer surplus: PS = IED = (100−4).32 = 1536 2
d. Identify relationship between variable profit (PS) that the firm gets before and after applying
perfect price discrimination and consumer surplus and deadweight loss ?
The relationship between variable profit for the firm applying price discrimination and consumer
surplus and deadweight loss is: VP = PS + CS + DWL