问题描述: 已知x=2y,化简根号y/(根号x-根号y)-根号y/(根号x+根号y) 1个回答 分类:综合 2014-10-05 问题解答: 我来补答 原式=√y/(√2y-√y)-√y/(√2y+√y)=√y/[√y(√2-1)]-√y/[√y(√2+1)]=1/(√2-1)-1/(√2+1)=(√2+1)/(√2+1)(√2-1)-(√2-1)/(√2+1)(√2-1)=(√2+1)/(2-1)-(√2-1)/(2-1)=√2+1-√2+1=2 展开全文阅读