# Question #d5864

##### 1 Answer

May 19, 2017

pi/8; (3pi)/8; (5pi)/8; (7pi)/8; (9pi)/8; (11pi)/8; (13pi)/8; (15pi)/8

#### Explanation:

cos 4x = 0

The unit circle gives 2 solutions:

a.

b.

8 answers for

k = 0 -->

k = 1 -->

k = 2 -->

k = 3 -->

k = 0 -->

k = 1 -->

k = 2 -->

k = 3 -->