cos, frac{pi }{{10}} ,cos, frac{2pi }{{1 | vedclass

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Question

$\pi /10 = 	heta$

$E =$$\frac{{2\,\sin 	heta \,(\cos 	heta \,.\,\cos 2	heta \,.\,\cos 4	heta \,.\cos 8	heta \,.\cos 16	heta \,)}}{{2\,\sin \

Vedclass · Accepted Answer

$-\frac{{\sqrt {10\,\, + \,\,2\sqrt 5 } }}{{64}}$

Vedclass · Answer

$\pi /10 = 	heta$

$E =$$\frac{{2\,\sin 	heta \,(\cos 	heta \,.\,\cos 2	heta \,.\,\cos 4	heta \,.\cos 8	heta \,.\cos 16	heta \,)}}{{2\,\sin 	heta }}$

$=$$\frac{{\sin 32	heta }}{{32\,\sin 	heta }}$

$=$$\frac{{\sin (30	heta \, + \,2	heta )}}{{32.\,\sin 	heta }}$ $=$ $ - \,\,\frac{1}{{16}}\,\cos \frac{\pi }{{10}}$

$=$ $ - \,\,\frac{1}{{16}}\,\,\sqrt {1 - {{\sin }^2}\pi /10} $

$cos\, \frac{\pi }{{10}} \,cos\, \frac{2\pi }{{10}} \,cos\,\frac{4\pi }{{10}}\, cos\,\frac{8\pi }{{10}}\, cos\,\frac{16\pi }{{10}}$ =

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