If $a{\sin ^2}x + b{\cos ^2}x = c,\,\,$$b\,{\sin ^2}y + a\,{\cos ^2}y = d$ and $a\,\tan x = b\,\tan y,$ then $\frac{{{a^2}}}{{{b^2}}}$ is equal to
$\frac{{(b - c)\,\,(d - b)}}{{(a - d)\,\,(c - a)}}$
$\frac{{(a - d)\,\,(c - a)}}{{(b - c)\,\,(d - b)}}$
$\frac{{(d - a)\,\,(c - a)}}{{(b - c)\,\,(d - b)}}$
$\frac{{(b - c)\,\,(b - d)}}{{(a - c)\,\,(a - d)}}$
$(\sec 2A + 1){\sec ^2}A = $
$\cos \frac{{2\pi }}{{15}}\cos \frac{{4\pi }}{{15}}\cos \frac{{8\pi }}{{15}}\cos \frac{{16\pi }}{{15}} =$
$cot 5^o$ -$tan5^o$ -$2$ $tan10^o$ -$4$ $tan 20^o$ -$8$ $cot40^o$ is equal to
If $\tan \theta = \frac{{\sin \alpha - \cos \alpha }}{{\sin \alpha + \cos \alpha }},$ then $\sin \alpha + \cos \alpha $ and $\sin \alpha - \cos \alpha $ must be equal to
If $A = 580^o$ then which one of the following is true