解方程[x/(x-1)]^2+[x/(x+1)]^2=40/9.
问题描述：
解方程[x/(x-1)]^2+[x/(x+1)]^2=40/9.
答
[x/(x-1)]^2+[x/(x+1)]^2=40/99x^2[(x+1)^2+(x-1)^2]= 40[(x+1)(x-1)]^29x^2(x^2+1)= 20(x^4-2x^2+1)11x^4-49x^2+20=0(11x^2-5)(x^2-4)=0x= 2 or -2 or √(5/11) or -√(5/11)