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1963 IMO Problems/Problem 5

Revision as of 17:23, 30 December 2008 by Minsoens (talk | contribs) (New page: ==Problem== Prove that <math>\cos{\frac{\pi}{7}}-\cos{\frac{2\pi}{7}}+\cos{\frac{3\pi}{7}}=\frac{1}{2}</math>. ==Solution== {{solution}} ==See Also== {{IMO box|year=1963|num-b=4|num-a=6...)
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Problem

Prove that $\cos{\frac{\pi}{7}}-\cos{\frac{2\pi}{7}}+\cos{\frac{3\pi}{7}}=\frac{1}{2}$.

Solution

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See Also

1963 IMO (Problems) • Resources
Preceded by
Problem 4 		1 • 2 • 3 • 4 • 5 • 6 Followed by
Problem 6
All IMO Problems and Solutions
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