# Exact Values of Trigonometric Values

1. Jul 13, 2008

### JBD2

I don't think this needs to go in the programming section as it has more to do with math than programming but anyways...

I'm currently writing a program for my calculator that will prompt the user to input a trigonometric value in either radians or degrees, so for example:
120° or $$\frac{2\pi}{3}$$

The program will then check if the principal angle (120) can be divided by 45, 30, and 60. If the quotient does not contain a decimal when divided by one of the "special angles" then the divisor was the reference angle. The problem is that an angle like 120 can be divided by 30 or 60, however 60 obviously gives a smaller quotient. So my question is this:

Is it safe to say that if an angle is divisible by both 60 and 30, then $$\pm$$60 is always the reference angle?

EDIT: That is any angles other than multiples of 180, correct?

Last edited: Jul 13, 2008