Use a sketch to find the exact value of \( y \). \( y=\sin \left[\cos ^{-1}\left(-\frac{24}{25}\right)\right] \)

th Sketching the Graph of a Trigonometric Function hs In Exercises 15-38, sketch the graph of the function. (Include two full periods.) \( \begin{array}{ll}\text { 15. } y=\frac{1}{3} \tan x & \text { 16. } y=\tan 4 x \\ \text { 17. } y=-2 \tan 3 x & \text { 18. } y=-3 \tan \pi x \\ \text { 19. } y=-\frac{1}{2} \sec x & \text { 20. } y=\frac{1}{4} \sec x \\ \text { 21. } y=\csc \pi x & \text { 22. } y=3 \csc 4 x\end{array} \)

2. a) Verify that \( \frac{\cos x}{1-\sin x}=\frac{1+\sin x}{\cos x} \) is true for \( x=\frac{\pi}{4} \). b) What are the non-permissible values for the equation?

\( 4tanx-ctgx=0 \)

- Convertir \( 45.3245^{\circ} \) a grados minutos y segundos

A salvage vessel locates a sunken ship 168 m below the water's surface. It determines that the angle of depression to one end of the ship is \( 47.6^{\circ} \) and to the other end is \( 65.1^{\circ} \). Determine the length of the ship.