(x+2)/(2x²-4x )÷ [(x-2)+(8x/(x-2)]= [(x+2)/2x(x-2 )]÷ [(x-2)^2+8x]/(x-2)= [(x+2)/2x(x-2 )]*[(x-2)/(x+2)^2]=1/x(x+2)x=√2 -1.原式=1/x(x+2)=1/[(√2 -1)(√2 +1)]=1/(2-1)=1
