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The polynomial: $8x^4-8x^2+1=\frac{\sqrt{3}}{2}$

I can simplify with $u=x^{2}$ to $8u^2-8u+{\frac{\sqrt{3}}{2}}=0$ Mistake $\left(1-\frac{\sqrt{3}}{2}\right)$

apply the quadratic formula: $\frac{-b\pm\sqrt{b^2-4ac}}{2a}$ $\frac{-(-8)\pm\sqrt{(-8)^2-4(8)\frac{\sqrt{3}}{2}} } {2a}$

reduces to: $u=1\pm \frac{\sqrt{64-16\sqrt{3}}}{2}$

That is what I have done. then I just take the square root of each value of u, and that will give me all 4 values?

I checked my result with wolfalpha. I don't understand why when it say completing the square did it add $1/4$ and not $\left(\frac{-b}{2}\right)$?

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    @RossMillikan have to wait 2 days.2012-09-15

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As Gerry Myerson pointed out, I made a mistake.

$8u^2-8u+\left(1-\frac{\sqrt{3}}{2}\right)=0$

the quadratic eq works here.