COMPLETA a. Se \( \alpha=\frac{\pi}{2} \rightarrow \cos \alpha=4 \) e \( \sin \alpha=0 \). b. \( \operatorname{se} \alpha=-\frac{\pi}{2} \rightarrow \cos \alpha=\square \) e \( \sin \alpha=\square \)

\( \sin \frac { \sin \theta } { 1 + \cos \theta } = \frac { 1 - \cos \theta } { \sin \theta } \)

\[ \cos 9 x \cdot \cos ^{3} x-\sin 9 x \cdot \sin 3 x=\sin 4 x \] denkleminin en kücük pozitif kökü kaç derecedir?

Simplity using the sum and difference identity d) \( \cos 3 x \cos 5 x-\sin 3 x \sin 5 x \)

mplify the following expressions without using a calculator \( \frac{\sin 210^{\circ} \cos 300^{\circ} \tan 240^{\circ}}{\cos 120^{\circ} \tan 150^{\circ} \sin 330^{\circ}} \) \( [\sin (-\theta)+\cos (360-\theta)]\left[\cos (90-\theta)+\frac{\sin \theta}{\tan \theta}\right] \) If \( \tan x=m+\frac{1}{m}, 90^{\circ} \leq x \leq 270^{\circ} \) and \( m+\frac{1}{m^{2}}=1 \) Calculate the value of \( x \) without the use of a calculator.

If \( \tan x=m+\frac{1}{m}, 90^{\circ} \leq x \leq 270^{\circ} \) and \( m^{2}+\frac{1}{m^{2}}=1 \) Calculate the value of \( x \) without the use of a calculator.