Okay so this was explained horribly to me in class, so I have no clue what I am doing.

I am stuck on these problems:

Sec^-1(1/2)

Arccos(sin(π/6))

tan(Csc^-1(2^-1))

It is asking me for an exact value, however I've never gone through this before and I am only familiar with radians and degrees. Please help.