1. The problem statement, all variables and given/known data Use the method of undetermined coefficients to find one solution of http://img85.imageshack.us/img85/6844/4ab921ad6ba6851cc91401c.png [Broken] Note that the method finds a specific solution, not the general one. 2. Relevant equations Y = Yc + Yp Yc = C1e^(r1t)+C2e^(rt) when roots are not the same. 3. The attempt at a solution For the homogeneous part I used the quadratic equation to get the roots -1 and -4. Y = Yc + Yp Yc = C1e^-t +C2e^-4t I tried Yp = (At^2+Bt+C)*De^(4t) but it doesn't seem correct after solving a bunch of derivatives and plugging it back into y'' + 3y' -4y and solving for constants. How to determine the Y-particular for this problem?