# Homework Help: Some Differential equation problems

1. Mar 14, 2006

### seang

Hey all, I'm reviewing for an exam and I'm in need of a bump on the following issues:

1.) Find the fundamental set of solutions for the given differential equation and initial point.

y'' + y' - 2y = 0 tsub0 = 0

2.)A spring is stretched 10cm by a force of 3 N. A Mass of 2kg is hung from the spring and attached to a damper which exerts 3 N when the velocity = 5m/sec. There's more but I just need a little help setting it up. I don't understand how to find y (as in yu'(t)). Unless its just 3/5.

Just a few hints would suffice, I'm not asking you to solve these.

Thanks, Sean

2. Mar 14, 2006

### stunner5000pt

for a) you have to assume that the solution looks like $$y(t) = Ce^{\lambda t}$$ where lambda is to be determined. Substitute this into your expression and you can find your lambda. Also use your initial condiotion to find C.