各位有能力的帮偶算一算：{1+[y/(x-y)}{1-[x/(x+y)]} 麻烦大家快一点,这是今晚作业,要过程,五分钟之内

各位有能力的帮偶算一算：{1+[y/(x-y)}{1-[x/(x+y)]} 麻烦大家快一点,这是今晚作业,要过程,五分钟之内
各位有能力的帮偶算一算：{1+[y/(x-y)}{1-[x/(x+y)]} 麻烦大家快一点,这是今晚作业,要过程,五分钟之内

各位有能力的帮偶算一算：{1+[y/(x-y)}{1-[x/(x+y)]} 麻烦大家快一点,这是今晚作业,要过程,五分钟之内
{1+[y/(x-y)}{1-[x/(x+y)]} =〔(x-y)/(x-y)+y/(x-y)〕〔(x+y)/(x+y)-x/(x+y)〕
=〔（x-y+y)/(x-y)〔（x+y-x)/(x+y)〕=xy/(x^2-y^2)