# Math Help - 1st order ODE?

1. ## 1st order ODE?

Dear friends,
Please suggest any method for the solution of the following equation:
$A(sin(at)+\frac{1}{2}sin(2at))+B(cos(at)+cos(2at)) =Dy(t)+\frac{dy}{dt}$
$y(t_1)=y_s$
$t\in(0,t_1)$

A,B,D,a=const
Thank you in advance.

2. Have you tried to find an integrating factor?

$I = e^{\int D~dt}$