$x$ ............ કિમત માટે $x = 1 - x + x^2 - x^3 + x^4 - x^5 + ......... \infty$ થાય 

$\frac{{\sin \theta + \sin 2\theta }}{{1 + \cos \theta + \cos 2\theta }} = $

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

જો $\frac{\sqrt{2} \sin \alpha}{\sqrt{1+\cos 2 \alpha}}=\frac{1}{7}$ અને  $\sqrt{\frac{1-\cos 2 \beta}{2}}=\frac{1}{\sqrt{10}}$ $\alpha, \beta \in\left(0, \frac{\pi}{2}\right),$ તો  $\tan (\alpha+2 \beta)$ મેળવો.

$sin\,10^o$ $sin\,30^o$ $sin\,50^o$ $sin\,70^o$ ની કિમત ....... થાય.

$\tan 7\frac{1}{2}^\circ   =...$