\( \sin^2 \theta + \cos^2 \theta = 1 \)
\( \tan \theta = \frac{\sin \theta}{\cos \theta} \)
\( \sec \theta = \frac{1}{\cos \theta} \)
\( \csc \theta = \frac{1}{\sin \theta} \)
\( \cot \theta = \frac{1}{\tan \theta} = \frac{\cos \theta}{\sin \theta} \)

\( \sin(\alpha \pm \beta) = \sin \alpha \cos \beta \pm \cos \alpha \sin \beta \)
\( \cos(\alpha \pm \beta) = \cos \alpha \cos \beta \mp \sin \alpha \sin \beta \)
\( \tan(\alpha \pm \beta) = \frac{\tan \alpha \pm \tan \beta}{1 \mp \tan \alpha \tan \beta} \)

\( \sin 2\theta = 2 \sin \theta \cos \theta \)
\( \cos 2\theta = \cos^2 \theta – \sin^2 \theta = 2\cos^2 \theta – 1 = 1 – 2\sin^2 \theta \)
\( \tan 2\theta = \frac{2\tan \theta}{1 – \tan^2 \theta} \)

الأحد الساعة 3.00 الفجر إن شاء الله