22. If \( \cos \theta=\frac{-15}{17} \) and \( \theta \) is obiuse, find without using tables the values of a) \( \operatorname{tun} \theta \) (2mks) \( \quad \sin \left(180^{\circ}-\theta\right) \)

3. Find the radian measure of each angle below: \( \begin{array}{llll}\text { (a) } 35^{\circ} & \text { (b) } 80^{\circ} & \text { (c) } 145^{\circ} & \text { (d) } 220^{\circ}\end{array} \)

14. Use the basic identities to find the values of the other five trigonometric functions given \( \sin x=-\frac{1}{2} \) and the angle \( x \) in the \( 4^{\text {th }} \) quadrant.

b. Se \( \alpha=-\frac{\pi}{2} \rightarrow \cos \alpha=0 \) esin \( \alpha=4 \). Aiutandoti con la circonferenza goniometrica, stabilisci se i seguenti valori sono positivi, negativi o nulti, \( \sin \left(-\frac{5}{2} \pi\right) ; \cos \frac{7}{6} \pi ; \sin 380^{\circ} ; \cos 452^{\circ} ; \sin 7 \pi ; \cos \left(-170^{\circ}\right) \).

Simplify the following expressions \( 6.1 \quad \frac{\sin 210^{\circ} \cos 300^{\circ} \tan 240^{\circ}}{\cos 120^{\circ} \tan 150^{\circ} \sin 330^{\circ}}\left[\begin{array}{l}{[\sin (-\theta)+\cos (360-\theta)]}\end{array}\right. \) If \( \tan x=m+\frac{1}{m}, 90^{\circ} \leq \) Calculate the value of \( x \)

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