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- #1

- Jan 26, 2012

- 4,055

**MarkFL**for proposing this problem for us to use![HR][/HR]

Using the triple-angle identity for cosine:

(1) $\displaystyle \cos(3\theta)=4\cos^3(\theta)-3\cos(\theta)$

solve the cubic equation:

(2) $\displaystyle 8x^3-6x-1=0$

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