This is a wonderful method.

来源: 于 2010-09-13 15:42:19 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

for x（a-x）（a+x）=[（1-c）x（a-x）（ca+cx）]/c（1-c）, why do you introduce c（1-c）. Is there any systematic patten to treat this kind of problem?