Question

How do you know when to and when not to use a trig function in a math problem?

Answer 1

lol, if you mean something like tan, sin, cos, csc, sec, cot, etc.
Well the problem would make it quite obvious. Do u have a specific problem?

Answer 2

No they didnt give me an equation

Answer 3

Then just write that it would be obvious to tell
for example, if you needed to find a specific angle or side, you would know when or when not to use it, when it's necessary, hwne it's not