यदि $\sin \theta + \sin 2\theta + \sin 3\theta = \sin \alpha $ तथा $\cos \theta + \cos 2\theta + \cos 3\theta = \cos \alpha $, तब $\theta$ का मान होगा
$\alpha /2$
$\alpha $
$2\alpha $
$\alpha /6$
यदि $\sin 6\theta = 32{\cos ^5}\theta \sin \theta - 32{\cos ^3}\theta \sin \theta + 3x,$ तब $x = $
यदि $\cos x + \cos y + \cos \alpha = 0$ तथा $\sin x + \sin y + \sin \alpha = 0,$ तब $\cot \,\left( {\frac{{x + y}}{2}} \right) = $
$\tan \alpha + 2\tan 2\alpha + 4\tan 4\alpha + 8\cot \,8\alpha = $
$1 - 2{\sin ^2}\left( {\frac{\pi }{4} + \theta } \right) = $
$(\sec 2A + 1){\sec ^2}A = $