91Ó°ÊÓ

In Exercises \(1-6,\) the measure of an angle is given. Classify the angle as acute, right, obtuse, or straight. $$ 83.135^{\circ} $$

Solve the right triangle shown in the figure. Round lengths to two decimal places and express angles to the nearest tenth of a degree. $$A=54.8^{\circ}, c=80$$

evaluate the trigonometric function at the quadrantal angle, or state that the expression is undefined. $$ \cos \pi $$

In Exercises \(13-20,\) convert each angle in degrees to radians. Express your answer as a multiple of \(\pi\). $$ 300^{\circ} $$

Use a calculator to find the value of each expression rounded to two decimal places. $$ \sin ^{-1} 0.47 $$

a. Use the unit circle shown for Exercises \(5-18\) to find the value of the trigonometric function. b. Use even and odd properties of trigonometric functions and your answer from part \((a)\) to find the value of the same trigonometric function at the indicated real number. $$ \begin{aligned} &a.\cos \frac{\pi}{3}\\\ &b.\cos \left(-\frac{\pi}{3}\right) \end{aligned} $$

In Exercises \(21-28,\) convert each angle in radians to degrees. $$ \frac{\pi}{2} $$

In Exercises 17–24, graph two periods of the given cotangent function. $$ y=-2 \cot \frac{\pi}{4} x $$

\(\theta\) is an acute angle and sin u is given. Use the Pythagorean identity \(\sin ^{2} \theta+\cos ^{2} \theta=1\) to find cos \(\theta.\) $$ \sin \theta=\frac{\sqrt{39}}{8} $$

find the exact value of each of the remaining trigonometric functions of \(\theta\) $$ \sin \theta=-\frac{12}{13}, \quad \theta \text { in quadrant III } $$