Question

All my calculations for whatever they're worth seem to point towards angle (theta) equaling 30 degrees when cos(theta) = sqrt(3)/2, as well as all the unit circle diagrams I'm coming across trying to figure this out... which would mean 30 degrees and 330 degrees; but my textbook says 60 and 300. Where is my err? (Or is the textbook wrong? Because there have been quite a few outright mistakes within it already...)

Answer 1

cos 300 and 30 is sqrt(3)/2 and cos 60 and 300 is 1/2 if my memory serves me right

Answer 2

right

Answer 3

textbook is wrong