1) For one question, the forcing term is 8cos2x - 4sinx. I am trying to solve by the method of undetermined coefficients. The solution to the homogeneous equation is c1cosx + c2sinx so for the particular solution I was using :(adsbygoogle = window.adsbygoogle || []).push({});

Acos2x + Bsin2x + Cxcosx + Dxsinx, where I added the x's into the last two terms because without those they would be solutions of the homogenous equation. Where am I going wrong here? I end up able to solve for A and B, but not for C and D. I have tried using convolutions but the constants become messy, and there are many many terms to deal with.

2) Another question is an eq of motion w/o damping with a forcing term of sinwt (w=omega). the question is "for what value of omega do oscillations increase unbounded?". I am not sure exactly what I am looking for here. My book mentions briefly the consequences of something being underdamped, and the frequency matching and making bridges collapse, etc, but nothing like this question. Where do I begin to look for the guidance to solve this type of question?

Any/all guidance is appreciated.

thx.

-A

**Physics Forums - The Fusion of Science and Community**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Ok, need a little help in a couple of areas (2nd order w/forcing terms)

Loading...

Similar Threads for need little help | Date |
---|---|

I Need a help in solving an equation (probably differentiation | Nov 20, 2017 |

I What differential equations need to be solved more quickly? | Feb 12, 2017 |

I need a little help on how does the iteration process. I know how | Aug 21, 2012 |

I need a little help with differentials | Mar 6, 2012 |

Little help needed for solving first order diffferential equation in NONLINEAR OPTICS | Feb 13, 2009 |

**Physics Forums - The Fusion of Science and Community**