ok the problem says to evaluate 690deg without a calculator
so i know 690 is 360deg+330deg
what do i do next? sin=330deg
and then how does it become -sin 30deg?
what i did was since i know sin is 330deg i looked it up on the unit circle and saw it corresponds to -1/2 since sin is the y-value.
what am i doing wromg, and if nothing, will my method always work?