જો $0 < x < \frac{\pi }{4}.$ તો $\sec 2x - \tan 2x = $
$\tan \left( {x - \frac{\pi }{4}} \right)$
$\tan \left( {\frac{\pi }{4} - x} \right)$
$\tan \left( {x + \frac{\pi }{4}} \right)$
${\tan ^2}\left( {x + \frac{\pi }{4}} \right)$
$\cot {70^o} + 4\cos {70^o} = . . .$
$cos\, \frac{\pi }{{10}} \,cos\, \frac{2\pi }{{10}} \,cos\,\frac{4\pi }{{10}}\, cos\,\frac{8\pi }{{10}}\, cos\,\frac{16\pi }{{10}}$ =
$1 + \cos \,{56^o} + \cos \,{58^o} - \cos {66^o} = $
$\sin {163^o}\cos {347^o} + \sin {73^o}\sin {167^o} = $
જો $\alpha$, $\beta$,$\gamma$ એ ધન સંખ્યાઓ છે કે જેથી $\alpha + \beta = \pi$ અને $\beta + \gamma = \alpha$ થાય તો $tan\ \alpha$= ................ (જ્યાં $\gamma \ne n\pi ,n \in I$ )