What are the phase shift and period for the function y=2cos1/2 (0+30*) - 4

I think there is a typo here. You did not type the question correctly. I will use what you gave us to work with.

y = A sin (Bx + c) + D

Period = 2pi/B

I assume that by 0 you meant to say 0x.

Period = 2pi/0, which is undefined.

I gotta stop here because you did not give us the correct equation to work with.