1.-1或2;2.0;3.1;4.2x-1/x
1 (x-2)/(x+2)=x-2 得出闷扮x=-1,x=22 f(x)+f(1/皮罩含x)=(1+x^2)/(1-x^2)+(1+(1/x)^2)/(1-(1/燃笑x)^2)=0