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VertexOperator
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Homework Statement
Evaluate:
Homework Equations
[tex]sin\frac{\pi }{7}.sin\frac{2\pi }{7}.sin\frac{3\pi }{7}[/tex]
The Attempt at a Solution
[tex]Using[/tex] [tex]z^{7}-1[/tex] [tex]got:[/tex]
[tex]cos\frac{\pi }{7}.cos\frac{2\pi }{7}.cos\frac{3\pi }{7}=\frac{1}{8}[/tex]
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