Calculus: Early Transcendentals 8th Edition

(a) $\frac{5\pi}{3}$ (b) $-\frac{\pi}{10}$
To convert from degrees to radians, we multiply the angle by $\frac{\pi}{180}$. (a) $300\times \frac{\pi}{180} = \frac{5\pi}{3}$ (b) $-18\times \frac{\pi}{180} = -\frac{\pi}{10}$