Using variation of parameters to solve a second order DE

i have to use variation of parameters method for this ode
$
\frac{d^2y}{dt^2} + w^2y = Eo sin(wt)
$

where Eo and w are constants

i have found the complementary function
$
Aexp(wit) + Bexp(-wit) or Ccos(wt) + Dsin(wt)
$

what are my y1 and y2 values?