cos theta= .5
2cos theta= .5
how do you do this?
If you are trying to solve for theta, then recall your commonly used angles.
cos 60° = .5
so, theta = 60°
2 cos theta = .5
so,
cos theta = .25
That's a bit tougher, so consult your calculator or a table of arccos, to find that
cos 75.5° = .25
so, theta = 75.5°
Judging from the question, I assume we're not worried about quadrants and reference angles...