The value of $cot\, 7\frac{{{1^0}}}{2}$ $+ tan\, 67 \frac{{{1^0}}}{2} - cot 67 \frac{{{1^0}}}{2} - tan7 \frac{{{1^0}}}{2}$ is :
a rational number
irrational number
$2(3 + 2 \sqrt 3)$
$2 (3 -\sqrt 3)$
$\frac{{\sin 3\theta - \cos 3\theta }}{{\sin \theta + \cos \theta }} + 1 = $
If $a\tan \theta = b$, then $a\cos 2\theta + b\sin 2\theta = $
$4 \,\,sin5^o \,\,sin55^o \,\,sin65^o$ has the values equal to
$\cos A + \cos (240^\circ + A) + \cos (240^\circ - A) = $
If $\frac{{2\sin \alpha }}{{\{ 1 + \cos \alpha + \sin \alpha \} }} = y,$ then $\frac{{\{ 1 - \cos \alpha + \sin \alpha \} }}{{1 + \sin \alpha }} = $