It has a period of 2pi
the equation to find the period of a sin/cos function is
[tex]period = \frac{2\pi}{b} [/tex]
y = -2 sin(x) has a normal period of 2pi because the b value in this equation isn't stated, making it equal to 1
the basic equation for a sin function is
[tex]y = a \: \sin(b(x - c) ) + d[/tex]