莫一笔带过小弟这道题实在不懂..

6个回答

原式=[x(x+1)/x+1-x^2/x+1]/[1/x^2/1-x^2+x^2/1-x^2]
=x/x+1*(1+x)(1-x)
=x(1-x)
=-√2(1+√2)
=-√2-2