解方程:(x/x-1)^2+(x/x+1)^2=40/9 ..= =

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解方程:(x/x-1)^2+(x/x+1)^2=40/9 ..= =

解方程:(x/x-1)^2+(x/x+1)^2=40/9 ..= =
解方程:(x/x-1)^2+(x/x+1)^2=40/9 ..= =

解方程:(x/x-1)^2+(x/x+1)^2=40/9 ..= =
1 [x/(x-1)]^2+[x/(x+1)]^2=40/9
[1/(1-1/X)]^2+[1/(1+1/X)]^2=40/9
x^2(2x^2+2)/[(x-1)(x+1)]^2
=2x^2(x^2+1)/[(x^2-1)]^2=40/9
即x^2(x^2+1)/[(x^2-1)]^2=20/9
设x^2=a
a(a+1)/(a-1)^2=20/9
9a^2+9a=20a^2-40a+20
9a^2+49a-20=0
a1=2,a2=5/11
所以x=±2 和x=±√55/11

(x/x-1)^2+(x/x+1)^2=40/9
9x^2[(.x-1)^2.+ (x+1)^2]=40(.x-1)^2.* (x+1)^2
9x^2[2x^2.+2]=40(.x-1)^2.* (x+1)^2
9x^4+9x^2=20(x^2-1)^2=20x^4-40x^2+20
11x^4-49x^2+20=0
(11x^2-5)(x^2-4)=0
则11x^2-5=0
或x^2-4=0
解得x=±根号55/11
x=±2