【John Dear】評論
不好意思~怎麼算出來的!!可以教教我嗎??
【我愛阿摩，阿摩愛我】評論
D(p)= Q = (p+1)^-2dQ/dp = -2(p+1)^-3 (dQ/Q) / (dp/p) = (dQ/dp) × (p/Q)= [-2 (p+1)^-3 ] × [p / (p+1)^-2]= -2p / (p+1)P=20-2 × 20 / (20+1) = -(40/21) = -1.90476P=10-2 × 10 / (10+1) = -(20/11) = -1.81818 http://tw.knowledge.yahoo.com/question/question?qid=1013070202925