[(x+y)平方-(x-y)平方】÷2xy 具体点
问题描述:
[(x+y)平方-(x-y)平方】÷2xy 具体点
答
[(x+y)^2-(x-y)^2】÷2xy
=[x^2+2xy+y^2-(x^2-2xy-y^2)]÷2xy
=[x^2+2xy+y^2-x^2+2xy-y^2]÷2xy
=4xy÷2xy
=2