...f \( (\mathrm{x})=0,5 \sin (\mathrm{x}) \) parallel zur Gerade \( \mathrm{y}=-0,25 \mathrm{x}+3 \) ? \( \square 0 \quad \square \frac{\pi}{3} \square 0,5 \pi \quad \square \frac{2}{3} \pi \) \( \square \pi \quad \square \frac{1}{3} \pi \quad \square 1,5 \pi \quad \square 1 \frac{2}{3} \pi \)

4. Найдите решения уравнения \( \cos 2 x=2 \cos x-1 \) на отрезке \( \left[-90^{\circ} ; 90^{\circ}\right] \).

2.1 If \( \hat{\mathrm{A}}=310^{\circ} \) and \( \hat{\mathrm{B}}=130,5^{\circ} \), determine the following values, correct to ONE decimal digit: \( 2.1 .1 \quad \tan 3 B+\frac{1}{3} \cos \frac{A}{3} \) \( 2.1 .2 \quad-\sec \left(\frac{A}{4}-2 B\right) \) 2.2 If \( \cot \theta=-\frac{12}{5} \) and \( \sin \theta>0 \), determine the value of \( 20 \operatorname{cosec} \theta-12 \sec \theta \), WITHOUT the use of a calculator. 2.3 Simplify the following expression: \( \frac{\sin \left(360^{\circ}-x\right) \sec \left(180^{\circ}+x\right)}{\tan \left(180^{\circ}-x\right) \operatorname{cosec}\left(360^{\circ}+x\right)} \)

2.4 Prove that: \[ \begin{array}{l}\frac{1}{1+\cot ^{2} x}+\frac{1}{1+\tan ^{2} x}=1 \\ 2.5 \text { Solve for } x \text { for } x \in\left[0^{\circ} ; 360^{\circ}\right], \text { correct to ONE decimal digit: } \\ -\frac{2}{3} \sin x+0,524=0\end{array} \]

Sea \( f(x)=7 \cos \left(x+\frac{\pi}{2}\right)+3 \). Entonces el mínimo valor que puede alcanzar \( f(x) \) es

You are given that \( \cos (A)=-\frac{3}{5} \), with \( A \) in Quadrant \( I I \), and \( \cos (B)=\frac{8}{17} \), with \( B \) in Quadrant \( I \). Find \( \cos (A-B) \). Give your answer as a fraction. Sorry, that's incorrect. Try again?