Differential equations - undetermined coefficients

[accountkiller]

Homework Statement

Find a particular solution of y'' + 2y' + 5y = e^x * sin(x)

Homework Equations

The Attempt at a Solution

Characteristic equation: r^2 + 2r + 5 = 0. Through quadratic formula, r1 = -1+2i and r2 = -1-2i, so my homogeneous equation is y_h = c1 * e^(-x) cos(2x) + c2 * e^(-x) * sin(2x).
Now, I need to use the undetermined coefficients method. How? I'm trying to figure out what exactly this undetermined coefficients method is, as my notes from lecture are confusing. And the e^x * sin(x) on the right looks like it would make things difficult.

I'd appreciate any guidance in the right direction, thanks!

 

[tiny-tim]

hi mbradar2!

(try using the X² and X₂ icons just above the Reply box )

there's a good guide at http://en.wikipedia.org/wiki/Undetermined_coefficients" , beginning …

the method of undetermined coefficients, otherwise known as the Lucky Guess Method …