化简，平方差公式处理后得√x+√y
原式=A÷BA=√x/√y-√y/√x=(x-y)/(√xy)B=(√x﹣√y)/(√xy)A/B=[(x-y)/(√xy)]/[(√x﹣√y)/(√xy)]=[(x-y)]/[(√x﹣√y)]=[(√x+√y)(√x﹣√y)]/[(√x﹣√y)]=√x+√y
