Solve the following expres3ion \( \sin 20^{\circ}+\sqrt{3} \sin 70^{\circ}= \) ?

4. Ölçüsü \( -\frac{125 \pi}{4} \) radyan olan açının esas ölçüsü kaçtır?

Da un punto \( P \) esterno a una circonferenza di centro \( C \) si mandano le tangenti \( P A \) e \( P B \). Sapen- do che \( \cos \wedge \widehat{P B}=-\frac{7}{25} \) e che \( P C=15 \mathrm{~cm} \), de- termina i valori delle funzioni goniometriche de- gli angoli \( C \widehat{P A} \) e \( P \widehat{C} A \) e il raggio della circonfe- renza. \( \left[\sin C P A=\frac{4}{5} ; \sin P \widehat{C A}=\frac{3}{5}, r=12 \mathrm{~cm}\right] \)

If \( \csc \theta=\frac{x+1}{x}, x>0 \), then \( \cot \theta= \)

Exercice 1: D. Ecrirc sous forme trigonométrique : \( z_{1}=2\left(\cos \frac{\pi}{4}-i \sin \frac{\pi}{4}\right) \) \( \begin{array}{ll}z_{2}=-3\left(\cos \frac{2 \pi}{3}+i \sin \frac{2 \pi}{3}\right) \quad z_{3}=2\left(\cos \frac{\pi}{4}+i \sin \frac{3 \pi}{4}\right) \\ z_{4}=\cos \frac{\pi}{6}+i \sin \left(-\frac{\pi}{6}\right) \quad z_{5}=\cos \theta-i \sin \theta \quad z_{5}=\sin \theta+i \cos \theta\end{array} \)

Вариант 6 1. Представить в тригонометрической и в показательной форме число \( z=-1-i \sqrt{3} \).