原式=[(x+1)/x]÷[(2x²/2x)-(x²+1)/2x]
=[(x+1)/x]÷[(2x²-x²-1)/2x]
=[(x+1)/x]×[2x/(x²-1)]
=2x(x+1)/[x(x+1)(x-1)]
=2/(x-1)
=2/(√2+1-1)
=2/√2
=√2