જો cos theta = frac{1}{2}left( {a + frac{1}{a | 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( {a + \frac

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]$

==> $\cos 3	heta = \frac{1}{2}\left( {{a^3} + \frac{1}{{{a^3}}}} ight)$.

જો $\cos \theta = \frac{1}{2}\left( {a + \frac{1}{a}} \right),$ તો $\cos 3\theta = . . .$

Similar Questions

જો $\sin 6\theta = 32{\cos ^5}\theta \sin \theta - 32{\cos ^3}\theta \sin \theta + 3x,$ તો $x = $

$\cos \frac{\pi }{7}\cos \frac{{2\pi }}{7}\cos \frac{{4\pi }}{7} = $

જો $\sin x + \cos x = \frac{1}{5},$ તો $\tan 2x = . . .$

$\cos 20^\circ \cos 40^\circ \cos 80^\circ = $

$\cos \left(\frac{2 \pi}{7}\right)+\cos \left(\frac{4 \pi}{7}\right)+\cos \left(\frac{6 \pi}{7}\right)$ ની કિંમત $\dots\dots$છે.