ب) $\tan^{2}\theta - \sin^{2}\theta = \sin^{2}\theta \tan^{2}\theta$

د) $\cos^{4}\theta - \sin^{4}\theta = 2\cos^{2}\theta - 1$

و) $(1 - \sin^{2}\theta)(1 + \tan^{2}\theta) = 1$

ح) $(\sin\theta + \cos\theta)^{2} + (\sin\theta - \cos\theta)^{2} = 2$

ی) $\frac{\cos\theta + 1}{\sin^{2}\theta} = \frac{1}{\sin\theta - \sin\theta \cos\theta}$

ل) $\frac{1}{\tan\theta + \frac{1}{\tan\theta}} = \sin\theta \cos\theta$