(x-1)^4/(x+1)^4 +(x-1)^2/(x+1)^2 +1 =0 |*(x+1)^4
(x-1)^4+(x-1)^2*(x+1)^2 + (x+1)^4=0
x^4-4x^3+6x^2-4x+1+(x^2-1)^2+x^4+4x^3+6x^2+4x+1=0
2x^4+12x^2+2+x^4-2x^2+1=0
3x^4+10x^2+3= 0
y=x^2
3y^2+10y+3=0
Δ=100-4*3*3=100-36=64
y1,2=(-10+/- √64)/2*3 =(-10 +/- 8)/6
y1=(-10+8)/6=-1/3 => x =i√1/3
y2=(-10-8)/6=-18/6=-3 => x=i√3
x€{i√1/2; i√3}
