$2 \sin \left(\frac{\pi}{22}\right) \sin \left(\frac{3 \pi}{22}\right) \sin \left(\frac{5 \pi}{22}\right) \sin \left(\frac{7 \pi}{22}\right) \sin \left(\frac{9 \pi}{22}\right)$ =
$\frac{3}{16}$
$\frac{1}{16}$
$\frac{1}{32}$
$\frac{9}{32}$
$\sin 12^\circ \sin 48^\circ \sin 54^\circ = $
$(sinx + cosecx)^2 + (cosx + secx)^2 - ( tanx + cotx)^2$ =
સાબિત કરો કે : $\frac{\sin x-\sin 3 x}{\sin ^{2} x-\cos ^{2} x}=2 \sin x$
જો $\sin \left( {x + \frac{{4\pi }}{9}} \right) = a;\,$ $\frac{\pi }{9}\, < \,x\, < \,\frac{\pi }{3},$ થાય તો $\cos \left( {x + \frac{{7\pi }}{9}} \right)$ =
$\cos 2(\theta + \phi ) - 4\cos (\theta + \phi )\sin \theta \sin \phi + 2{\sin ^2}\phi = $