cos theta= .5

Question

2cos theta= .5

how do you do this?

Answer 1

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...