Question: hi im okay with most of the question but i...

Hi, I'm okay with most of the question, but I always have trouble working out the extra reference angles depending on the domain. So, in PREP 2 question, I can get that it's pi/4 as the ref angle for tan, but how do i get all the other ref angles given the domain? I never know if it's pi + or pi subtract or 2pi or whatever. If you could help with that part for PREP 1 and PREP 2 questions, that would be really helpful, thanks heaps as ever, Michael