Think "Reference Angle". Look it up and show us what you get.
Remember that we can rewrite coterminal angles by adding (or subtracting ) multiples of 2 Pi.
The first tells us to go around the unit circle 5 times (10 Pi radians)and the Pi/3 more times so
Will have the same out put for trig functions.
This diagram should help you discover that sine is an odd function.
Take a look and see if you can convince yourself. If you have any more questions just ask.