यदि cos theta = frac{1}{2}left( {a + frac{1}{ | vedclass

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

Question

(c) $\because$ $\;\cos 3	heta  = 4{\cos ^3}	heta  - 3\cos 	heta $ 

$	herefore \cos 3	heta = 4\frac{1}{{{2^3}}}{\left(

Vedclass · Accepted Answer

$\frac{1}{2}\left( {{a^3} + \frac{1}{{{a^3}}}} \right)$

Vedclass · Answer

(c) $\because$ $\;\cos 3	heta  = 4{\cos ^3}	heta  - 3\cos 	heta $ 

$	herefore \cos 3	heta = 4\frac{1}{{{2^3}}}{\left( {a + \frac{1}{a}} ight)^3} - 3\frac{1}{2}\left( {a + \frac{1}{a}} ight)$

$ \Rightarrow \cos 3\,	heta = \frac{1}{2}\left( {a + \frac{1}{a}} ight)\,\left[ {{{\left( {a + \frac{1}{a}} ight)}^2} - 3} ight]$ 

==> $\cos 3	heta = \frac{1}{2}\left( {{a^3} + \frac{1}{{{a^3}}}} ight)$.

यदि $\cos \theta = \frac{1}{2}\left( {a + \frac{1}{a}} \right),$ तब $\cos 3\theta $ का मान होगा

Similar Questions

$\tan 5x\tan 3x\tan 2x = $

$\frac{{\sqrt {1 + \sin x} + \sqrt {1 - \sin x} }}{{\sqrt {1 + \sin x} - \sqrt {1 - \sin x} }} , \,\,($ जब $x \, \in $ द्वितीय चतुर्थांष $) =$

यदि $cos A = {3\over 4} , $ तब $32\sin \left( {\frac{A}{2}} \right)\sin \left( {\frac{{5A}}{2}} \right) = $

यदि $A, B, C$ किसी त्रिभुज के कोण हों, तो $\sin 2A + \sin 2B - \sin 2C$ का मान होगा

$\sin 10^{\circ} \sin 30^{\circ} \sin 50^{\circ} \sin 70^{\circ}$ का मान है