1. The problem statement, all variables and given/known data Find a particular solution for these second order differential equations. 2. Relevant equations 1) y''+9y=tan3t 2) y''+y=tan^2t 3. The attempt at a solution I want to find a fundamental solutions y1 and y2 cuz I want to find a particular solution like this y=v1*y1+v2*y2, but i don't know how to get them.