Cos/tan/sin questions with pi intervals

There are multiple c2 question where you have to use identities ies to solve x with cos/tan/sin equations and i know how to rearrange and get it to only one of them but how does the interval - pi <x< pi affect how i solve for pr x.

There are multiple c2 question where you have to use identities ies to solve x with cos/tan/sin equations and i know how to rearrange and get it to only one of them but how does the interval - pi <x< pi affect how i solve for pr x.

I may be telling you the entirely incorrect thing but as your doing c2 i assume you are sitting the new spec of maths. pi is pi RADIANS which is a unit for angles which isnt degrees. 1 pi radian is 180 degrees.
However dont fear as if you are doing edexcel 2017 spec then you dont need to know radians