I have the following
So the auxilary equation would look like
The solution to this equation is on the form
which evaluates to
but apparently thats incorrect, the answer should be
Edit: Darn i just remebered there's a forum for DE's. I can't delete my post
I have attached the solution to your question. Hope it will help you to find where you went wrong. But I would greatly appreciate your reply in whether you were able to read my attachment clearly. If it is not clear or if you have any doubt regarding this question please don't hesitate to mail me.