can i do a square root here?
assuming I cant I went on and did
how .. do I do this.. especially without the unit circle
I looked at the answers and the values are not on the unit circle.
does NOT equal .
So far you have two possibilities:
Cosine is positive in the first and fourth quadrants, and to get to , you have to "undo" the cosine - so take the arccos (or ...
, since the period of cosine is .
, since cosine is negative in the second and third quadrants and the period is
So putting it all together, the possibilities are