If $\alpha = 22^\circ 30',$ then $(1 + \cos \alpha )(1 + \cos 3\alpha )$ $(1 + \cos 5\alpha )(1 + \cos 7\alpha )$ equals
$1/8$
$1/4$
$\frac{{1 + \sqrt 2 }}{{2\sqrt 2 }}$
$\frac{{\sqrt 2 - 1}}{{\sqrt 2 + 1}}$
Convert $6$ radians into degree measure.
If $\sin x + {\rm{cosec}}\,x = 2,$ then $sin^n x + cosec^n x$ is equal to
Which of the following is correct
If for real values of $x,\cos \theta = x + \frac{1}{x},$ then
If $\cos \theta = \frac{1}{2}\left( {x + \frac{1}{x}} \right)$, then $\frac{1}{2}\left( {{x^2} + \frac{1}{{{x^2}}}} \right) = $