91Ó°ÊÓ

Verifying a Trigonometric ldentity In Exercises \(9-50\) , verify the identity. $$\tan t \cot t=1$$

Solving a Multiple-Angle Equation, find the exact solutions of the equation in the interval \(0,2 \pi )\) $$\cos 2 x-\cos x=0$$

Evaluating Exerrises \(7-10,\) find the exact value of each expression. $$ \sin \left(135^{\circ}-30^{\circ}\right) \quad \text { (b) } \sin 135^{\circ}-\cos 30^{\circ} $$

Evaluating Exerrises \(7-10,\) find the exact value of each expression. $$ \cos \left(120^{\circ}+45^{\circ}\right) \quad \text { (b) } \cos 120^{\circ}+\cos 45^{\circ} $$

Verifying Solutions In Exercises \(5-10\) , verify that the \(x\) -values are solutions of the equation. $$\begin{array}{l}{\csc ^{4} x-4 \csc ^{2} x=0} \\ {\text { (a) } x=\frac{\pi}{6}}\end{array}$$ $$x=\frac{5 \pi}{6}$$

Solving a Multiple-Angle Equation, find the exact solutions of the equation in the interval \(0,2 \pi )\) $$\cos 2 x+\sin x=0$$

Use the given values to find the values (if possible) of all six trigonometric functions. \(\sin (-x)=-\frac{1}{3}, \quad \tan x=-\frac{\sqrt{2}}{4}\)

Verifying a Trigonometric ldentity In Exercises \(9-50\) , verify the identity. $$\sec y \cos y=1$$

Solving a Trigonometric Equation In Exercises \(11-24,\) solve the equation. $$\sqrt{3} \csc x-2=0$$

Verifying a Trigonometric ldentity In Exercises \(9-50\) , verify the identity. $$\cot ^{2} y\left(\sec ^{2} y-1\right)=1$$