先化简再求值:(1-1/2)除以x²-2x+1/x²-1,其中x=2
问题描述：
先化简再求值:(1-1/2)除以x²-2x+1/x²-1,其中x=2
答
原式=1/2÷(x-1)²/(x+1)(x-1)
=1/2÷(x-1)/(x+1)
=1/2×(x+1)/(x-1)
=(x+1)/(2x-2)
=(2+1)/(4-2)
=3/2