Thread: trig help

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?

thanks!

figured it out,...can the mods please delete this? thanks.