cos frac{pi }{5}cos frac{{2pi }}{5}cos frac{{ | vedclass

Name: PDF Generator App | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(d) $\cos \frac{\pi }{5}\cos \frac{{2\pi }}{5}\cos \frac{{4\pi }}{5}\cos \frac{{8\pi }}{5}$

$ = \frac{{\sin \frac{{{2^4}\pi }}{5}}}{{{2^4}\sin \fra

Vedclass · Accepted Answer

$-1/16$

Vedclass · Answer

(d) $\cos \frac{\pi }{5}\cos \frac{{2\pi }}{5}\cos \frac{{4\pi }}{5}\cos \frac{{8\pi }}{5}$

$ = \frac{{\sin \frac{{{2^4}\pi }}{5}}}{{{2^4}\sin \frac{\pi }{5}}} = \frac{{\sin \frac{{16\pi }}{5}}}{{16\,\sin \frac{\pi }{5}}} $

$= \frac{{\sin \,\left( {3\pi + \frac{\pi }{5}} \right)}}{{16\,\sin \frac{\pi }{5}}}$

$ = \frac{{ - \sin \frac{\pi }{5}}}{{16\,\sin \frac{\pi }{5}}} = - \frac{1}{{16}}$.

$\cos \frac{\pi }{5}\cos \frac{{2\pi }}{5}\cos \frac{{4\pi }}{5}\cos \frac{{8\pi }}{5} = $

Similar Questions

माना $\alpha ,\beta $ इस प्रकार है कि $\pi < (\alpha - \beta ) < 3\pi $. यदि $\sin \alpha + \sin \beta = - \frac{{21}}{{65}}$ तथा $\cos \alpha + \cos \beta = - \frac{{27}}{{65}},$ तो $\cos \frac{{\alpha - \beta }}{2}$ का मान है

यदि $0 < x < \frac{\pi }{4}$, तब $\sec 2x - \tan 2x$ का मान होगा

निम्नलिखित को सिद्ध कीजिए

$\frac{\sin x-\sin 3 x}{\sin ^{2} x-\cos ^{2} x}=2 \sin x$

$\sqrt 2 + \sqrt 3 + \sqrt 4 + \sqrt 6 = $

यदि $A + B + C = \pi \,(A,B,C > 0)$ तथा $C$ अधिककोण है, तब