## Trigonometry 7th Edition

a) $60^{\circ} + 360^{\circ}k$ and $300^{\circ} + 360^{\circ}k$, for all integers $k$. b) $60^{\circ}, 300^{\circ}$
b) Isolate $cos\theta$ $2cos\theta = 1$ $cos\theta = \frac{1}{2}$ Recall knowledge about the unit circle $cos\theta$ is positive in quadrant I and IV - Angles $60˚$ and $300˚$ Therefore, $cos\theta = \frac{1}{2}$ for $\theta = 60˚, 300˚$ a) Take the two angles and add $360^{\circ}k$, for all integers $k$, to find all degree solutions. $60^{\circ} + 360^{\circ}k$ and $300^{\circ} + 360^{\circ}k$, for all integers $k$.