令PMT = 每月平均攤還本息. PV = 貸款總金額. r = 月利率. N = 貸款期數. 則PV = PMT * (1+r)-1 + PMT * (1+r)-2 + ... + PMT * (1+r)-N. 兩邊同乘以 (1+r),.
tw.knowledge.yahoo.com