Arctangent confusing to me

[AmySaunders]

This is my problem and I can not figure it out!!!:
Arctan[tan(7pi/6)]
I have tried to use the reference triangles but no matter what I do, I always come out with the answer: 7pi/6. The answer book, however, says that the answer is pi/6. Any and all help will be appreciated!!

[Martingale]

This is my problem and I can not figure it out!!!:
Arctan[tan(7pi/6)]
I have tried to use the reference triangles but no matter what I do, I always come out with the answer: 7pi/6. The answer book, however, says that the answer is pi/6. Any and all help will be appreciated!!

can't be an answer since is always between

[Martingale]

Any and all help will be appreciated!!

remember that tan is pi periodic.

so

[AmySaunders]

I'm sorry. I still don't understand? Is there a lesson on here you could refer me to? What does pi periodic mean?

[Martingale]

What does pi periodic mean?

http://www.wolframalpha.com/input/?i=graph+tan%28x%29

notice how the graph repeats..it does this very pi units