Question

Please help me with these two trig questions!

Answer 1

\[\cos^{-1} (1/2)\]

Answer 2

\[\sin^{-1} (\sqrt{3}/2)\]

Answer 3

these are special values you really just have to memorize, though you will develop an intuition for them with time
for now, here is a cheat sheet (look at the part with the unit circle)
http://tutorial.math.lamar.edu/pdf/Trig_Cheat_Sheet.pdf

Answer 4

find the angle(s) in radians that correspond to values of cosine and sine you have written