यदि $\frac{x}{{\cos \theta }} = \frac{y}{{\cos \left( {\theta - \frac{{2\pi }}{3}} \right)}} = \frac{z}{{\cos \left( {\theta + \frac{{2\pi }}{3}} \right)}},$ तो $x + y + z = $
$1$
$0$
$ - 1$
इनमें से कोई नहीं
यदि $\theta $ न्यून कोण है तथा $\sin \frac{\theta }{2} = \sqrt {\frac{{x - 1}}{{2x}}} $, तो $\tan \theta $ का मान है
$3\,\left[ {{{\sin }^4}\,\left( {\frac{{3\pi }}{2} - \alpha } \right) + {{\sin }^4}\,(3\pi + \alpha )} \right]$ $ - 2\,\left[ {{{\sin }^6}\,\left( {\frac{\pi }{2} + \alpha } \right) + {{\sin }^6}(5\pi - \alpha )} \right] = $
यदि $\tan \theta = t,$ तो $\tan 2\theta + \sec 2\theta = $
यदि $\sin A + \cos A = \sqrt 2 ,$ तो ${\cos ^2}A = $
$\cos A + \cos (240^\circ + A) + \cos (240^\circ - A) = $