1. The problem statement, all variables and given/known data Given DE is D^2(y)+5Dy+4y=cos 2x ........where D=>(dy/dx) We are to find the general solution.(I have done it already) Is the particular integral unique?If not,find another PI and show that the general solution is the same for all PI. 2. Relevant equations 3. The attempt at a solution I did the first part and got the general solution as y=C1 exp(-x)+C2 exp(-4x)+(1/10)cos 2x I cannot understand why the PI would be non-unique?Can anyone please check if I am correct in having that answer?