# How do you evaluate arccos (1/2)?

Jun 9, 2015

Find arccos (1/2)

#### Explanation:

Trig Table gives:

$\cos x = \frac{1}{2} - \to x = \frac{\pi}{3} \mathmr{and} 60 \mathrm{de} g$

Trig unit circle gives another arc x that has the same cos value (1/2):

x = - 60 deg, or x = 360 - 60 = 300 deg

Answers within period $\left(0 , 2 \pi\right)$: 60 deg and 300 deg