(x-y/1-x+y/1)÷2y/y-x计算错了,是(1/x-y-1/x+y)÷2y/y-x

问题描述:

(x-y/1-x+y/1)÷2y/y-x计算
错了,是
(1/x-y-1/x+y)÷2y/y-x

[1/﹙x-y﹚-1/﹙x+y﹚]÷2y/﹙y-x﹚
=﹙x+y-x+y﹚/﹙x²-y²﹚·﹙y-x﹚/2y
=2y/﹙x-y﹚﹙x+y﹚·2y/﹙y-x﹚
=﹣1/﹙x+y﹚.