A Rule of Thumb for Pricing(定价的简单（经验）法则) MR=△R/△Q=△(PQ)/△Q=P+Q(△P/△Q) =P+P(QP)(△P/△Q)=P+P(△P/P)/△Q/Q) =P+P(1/E) Because the firm's objective is to maximize profit,we can set marginal revenue equal to marginal cost: MR=P+P(1/E)=MC Which can be rearranged to give us P-MC)/P=-(1/Ea) MR = △R/△Q = △(PQ)/△Q = P + Q (△P/△Q ) = P + P(Q/P) (△P/△Q ) = P + P (△P/P)/(△Q/Q ) = P + P (1/Ed ) Because the firm’s objective is to maximize profit, we can set marginal revenue equal to marginal cost: MR = P + P (1/Ed ) = MC Which can be rearranged to give us (P – MC)/P = - (1/Ed ) A Rule of Thumb for Pricing (定价的简单(经验)法则)