The standard form of equation for the sin function is y = Asin(Bx-C) where A is amplitude, Period is 2π/B, and the phase shift is equal to Bx-C set to zero. C is then obtained in this equation.
For given problem: A is equal to 2, period=2π/B=2π/1=2π, where B is equal to 1. Period then is equal to A. 2pi