How does $\sin(x-2\pi) = \sin(x)$? How does $\sin(x-2\pi) = \sin(x)$? Is it so that you can split $\sin(x-2\pi)$ into $\sin(x) - \sin(2\pi)$ and that equals $\sin(x) - 0 = \sin(x)$? Please help. Thank you

Sine is a periodic function with period 2$\pi$.  Perhaps the easiest way to see this is to use the formula $\sin(a+b) = \sin(a)\cos(b) + \cos(a)\sin(b)$
