यदि $\sec \theta + \tan \theta = p,$ तब $\tan \theta $ बराबर है
यदि $A + C = B,$ तब $\tan A\,\tan B\,\tan C = $
$\frac{{2\sin \theta \,\tan \theta (1 - \tan \theta ) + 2\sin \theta {{\sec }^2}\theta }}{{{{(1 + \tan \theta )}^2}}} = $
यदि $\tan \theta = \frac{{x\,\sin \,\phi }}{{1 - x\,\cos \,\phi }}$ तथा $\tan \,\phi = \frac{{y\sin \,\theta }}{{1 - y\,\cos \,\theta }}$, तो $\frac{x}{y} = $
सिद्ध कीजिए
$(\cos x+\cos y)^{2}+(\sin x-\sin y)^{2}=4 \cos ^{2} \frac{x+y}{2}$