Homework Help: Mechanical Vibrations Differential Equation

1. Oct 22, 2011

Goatsenator

1. The problem statement, all variables and given/known data

Find the general solution for the differential equation

2. Relevant equations

y'' + 16y = tan(4t)

3. The attempt at a solution

I get C1cos(4t) + C2sin(4t) = 0 for my homogeneous equation.

I did the usual method of undetermined coefficients (I think I took all of the derivatives correctly). However I'm getting something strange for yp. I can't really make sense of the solution. Does this have something to do with the fact that the tangent function has discontinuities? Would this be some kind of resonance?

Last edited: Oct 22, 2011
2. Oct 22, 2011

rock.freak667

There is no sort of 'fixed' form for the PI of tan(4t), you might need to try variation of parameters to solve it.

3. Oct 22, 2011

Goatsenator

Oh yeah! Thanks for the help!