CPM Homework Help : A2C Problem 11-45

Use reference angles, the symmetry of a circle, and the knowledge that $\operatorname { cos } ( \frac { \pi } { 3 } ) = \frac { 1 } { 2 }$ to write three other true statements using cosine and angles that are multiples of $\frac { \pi } { 3 }$ .

Example 1:

$\text{cos}\left(\frac{2\pi}{3}\right) = -\frac{1}{2}$

Example 2:

cos(π) = −1

Example 3:

$\text{cos}\left(-\frac{\pi}{3}\right) = \frac{1}{2}$

Now come up with your own examples.