19 Multiple Choice 1 point Find the exact value \( \cos \left(\tan ^{-1} \frac{8}{15}-\cos ^{-1} \frac{3}{5}\right) \) \( \frac{77}{85} \) \( -\frac{8}{85} \) \( \frac{8}{85} \) \( -\frac{77}{85} \)

Al reducir la expresión CscaTanaCosa-Csc \( 2 a ~ a ~ u n a ~ s o l a ~ f u n c i o ́ n ~ t r i g o n o m e ́ t r i c a ~ s e ~ o b t i e n e: ~ \) \( 2 \operatorname{sen}^{2} a \) \( -\sec ^{2} a \) \( -\cot ^{2} a \)

Convert the angle \( \theta=\frac{5 \pi}{12} \) radians to degrees. Express your answer exactly. \( \theta=\square \)

В треугольнике \( A B C \) угол \( C \) равен \( 90^{\circ}, B C=72 \) \( A B=75 \). Найдите \( \cos B \).

Verify that \( (\cos \theta)^{2}+(\sin \theta)^{2}=1 \) for when \( \theta=75^{\circ} \) atement.

value of: \( \frac{\sin \theta+\cos \theta}{2 \sin \theta} \) without using a calculator. \( 4.2 .1 \tan \left(-32^{\circ}\right) \) \( 4.2 .2 \sin 412^{\circ} \) Simplify the following fully and without using a calculator: \( \frac{\sin 120^{\circ} \cdot \tan 300^{\circ}}{\cos \left(-60^{\circ}\right) \cdot \tan 225^{\circ}} \) Prove the following identity: \( \frac{\cos 2 x-\cos x-\sin x}{2 \sin x \cos x+\sin x}=\frac{1}{\tan x}-\frac{1}{\sin x} \) Determine the general solution of: \( \sin (5 \theta)=\cos \left(\theta-40^{\circ}\right) \)