If ${\cos ^6}\alpha + {\sin ^6}\alpha + K\,{\sin ^2}2\alpha = 1,$ then $K =$
$\frac{4}{3}$
$\frac{3}{4}$
$\frac{1}{2}$
$2$
If $\tan \frac{\theta }{2} = t,$then $\frac{{1 - {t^2}}}{{1 + {t^2}}}$is equal to
$\frac{{\sqrt 2 - \sin \alpha - \cos \alpha }}{{\sin \alpha - \cos \alpha }} = $
If $A$ and $B$ are complimentary angles, then :
The value of the expression $(sinx + cosecx)^2 + (cosx + secx)^2 - ( tanx + cotx)^2$ wherever defined is equal to
The value of $tan^{-1} (\frac{sin2 -1}{cos2})$ is equal to:-