A nonhomogeneous differential equation in the linear setting is a differential equation of the form
in which is a linear operator on
functions and the forcing term
is not identically zero. The associated homogeneous differential
equation is
.
If
is one particular solution of the nonhomogeneous
equation and
is an arbitrary solution of the associated homogeneous differential
equation, then every solution of the nonhomogeneous equation has the form
Methods for finding include variation
of parameters and the undetermined
coefficients method.