Diff Eq question

[Shooters]

Okay, it's been a while since I took this course, and I have a quick question. Let's say I have a diff eq of the form m*u'' + k*u = constant. Then the solution is going to be the sum of the complemetary (homogenous) solution and the particular solution: u(t) = ucomplemetary + uparticular. Now, let's say I have initial conditions u(0) = u'(0) = 0. When I use the initial conditions to find the coefficients in the solution, do I use them in just the complementary solution, or do I need to use them in the complementary + particular?