annihilator method

Etymology
From its use of an (in this case a differential operator) to render the equation more tractable.

Noun

 * 1)  A procedure used to find a particular solution to certain types of inhomogeneous ordinary differential equation.

Usage notes
The term undetermined coefficients is sometimes used to refer to the step in the procedure when the coefficients are calculated. (Note, however, that the  is a separate, although closely related, method.)