Prove that: \[ \frac{\cos \theta-\sin \theta}{\cos \theta+\sin \theta}=\sec 2 \theta-\tan 2 \]

4. (s) Diben \( \operatorname{lan} \theta=-1.4826 \) dan \( 180^{\circ} \leq \theta \leq 360^{\circ} \) hilung sudul \( \theta \) Given than \( \tan \theta=-1.4826 \) ond \( 180^{\circ} \leq 0 \leq 360^{\circ} \). calculate angle \( \theta \)

Which of the following can be written as \( \sin 9 x \) ? \( \begin{array}{l}\sin 5 x \cos 4 x-\cos 5 x \sin 4 x \\ \sin 5 x \cos 4 x+\cos 5 x \sin 4 x \\ \cos ^{2} 5 x-\sin ^{2} 4 x \\ 0 \cos ^{2} 5 x+\sin ^{2} 4 x \\ \text {-out of } 1 \\ \text { Previous page }\end{array} \) P

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

Simplifier: \( B=3 \cos 10^{\circ}+5 \cos ^{2} 15^{\circ}+5 \cos ^{2} 75^{\circ}-3 \sin 80^{\circ} \)

25. यदि लगाउनुहोस् । If \( 9 \cos \theta+40 \sin \theta=41 \), find the value of \( \tan \theta \).