i have the equation

r(t) = sin(2t)i + 2cos(t)j where 0<t<2pi

I have to prove that using this equation that the object it describes passes through the origin twice in the time limit. Does this just mean I have to show the values of t that give r(t) = 0? i.e. pi/2 and 3pi/2?

cheers for the help