Answer:
theta = 135+ n360
theta = 225+n360
Explanation:
-sqrt(2) = 2 cos theta
Divide each side by 2
-sqrt(2)/2 =2/2 cos theta
-sqrt(2)/2 = cos theta
Take the inverse cos on each side
arccos (-sqrt(2)/2) = arc cos(cos theta)
135 = theta
Now remember this only gives you the value between 0 and 180 degrees.
Take 360 minus the value found to get the other angle since this is cosine
360 -135 = 225
Now remember this is cyclical, so we can add 360 to each of these values and we will get the same amount
theta = 135+ n360
theta = 225+n360