સાબિત કરો કે, $=\frac{\sin 5 x-2 \sin 3 x+\sin x}{\cos 5 x-\cos x}=\tan x$
We have
${\text{L}}{\text{.H}}{\text{.S}}{\text{.}}\frac{{\sin 5x - 2\sin 3x + \sin x}}{{\cos 5x - \cos x}}$
$ = \frac{{\sin 5x + \sin x - 2\sin 3x}}{{\cos 5x - \cos x}}$
$ = \frac{{2\sin 3x\cos 2x - 2\sin 3x}}{{ - 2\sin 3x\sin 2x}}$
$ = - \frac{{\sin 3x(\cos 2x - 1)}}{{\sin 3x\sin 2x}}$
$ = \frac{{1 - \cos 2x}}{{\sin 2x}}$
$ = \frac{{2{{\sin }^2}x}}{{2\sin x\cos x}}$
$ = \tan \,x = R.H.S$
જો $A + B + C = {180^o},$ તો $\cot \frac{A}{2} + \cot \frac{B}{2} + \cot \frac{C}{2} = . . .$
જો $\cos \left( {\alpha + \beta } \right) = \frac{4}{5}$ અને $\sin \left( {\alpha - \beta } \right) = \frac{5}{{13}}$,કે જ્યાં $0 \le \alpha ,\beta \le \frac{\pi }{4}$. તો $\tan 2\alpha $ મેળવો.
સમીકરણ $\frac{{{{\tan }^2}20^\circ - {{\sin }^2}20^\circ }}{{{{\tan }^2}20^\circ \,\cdot\,{{\sin }^2}20^\circ }}$ =
જો ${\tan ^2}\theta = 2{\tan ^2}\phi + 1,$ તો $\cos 2\theta + {\sin ^2}\phi = . . .$
સાબિત કરો કે : $\cos 4 x=1-8 \sin ^{2} x \cos ^{2} x$