已知0已知0
已知0先求(a+b)^2/(a-b)^2 (a+b)^2=a^2+b^2+2ab=8ab (a-b)^2=a^2+b^2-2ab=4ab 所以(a+b)^2/(a-b)^2=2 (a+b)/(a-b)=根号2