If $x = sec\, \phi - tan\, \phi$ & $y = cosec\, \phi + cot\, \phi$ then :
$xy + x - y + 1 = 0$
$y = \frac{{1\,\, + \,\,x}}{{1\,\, - \,\,x}}$
$x = \frac{{y\,\, - \,\,1}}{{y\,\, + \,\,1}}$
All of the above
$1 + \cos 2x + \cos 4x + \cos 6x = $
If $\sin 2\theta + \sin 2\phi = 1/2$ and $\cos 2\theta + \cos 2\phi = 3/2$, then ${\cos ^2}(\theta - \phi ) = $
If $A, B, C$ are acute positive angles such that $A + B + C = \pi $ and $\cot A\,\cot \,B\,\cot \,C = K,$ then
The value of $cosec \frac{\pi }{{18}} - \sqrt 3 \,sec\, \frac{\pi }{{18}}$ is a
Which of the following functions have the maximum value unity ?