Hey guys, was just looking through some inverse questions and i got stuck at a certain one. Upon looking at the answers i was shocked, i had never seen anything like it.

3Cos-1(2x+1) - pie/2, Find the domain.

Okay so the only thing that affects the domain in this function is the 2x+1. Of the cos-1(x) function, the domain is -1,1. So since 2x = -1, x= -1/2, shouldnt the new domain be [-1.5,.5]. The answer they gave me was [-1,0]. Is their some rule that applies for shifting the inverse functions across???