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View Full Version : System of Coulped ODE's/ Panic Attack


H-bar None
Mar29-07, 03:54 PM
1. The problem statement, all variables and given/known data

dx/dt = -xy

dy/dt =-xy

find x(t) and y(t)


3. The attempt at a solution

Using Maple I've plotted the vector field and solution curve for a list of initial conditions. When I tried to work by hand I could find a way to uncoulple the equations. Is there an analytical solution? Method (linearization and etc. )works best? I've sifted through numerous textbooks and couldn't find a decent example.
1. The problem statement, all variables and given/known data



2. Relevant equations



3. The attempt at a solution

Dick
Mar29-07, 04:07 PM
As a first step I would integrate dx/dt=dy/dt.

H-bar None
Mar29-07, 06:44 PM
Are you telling me its that simple?

Could you go a little further?

pki15
Mar29-07, 09:07 PM
1st solve dy/dt = dx/dt. You should then be able to solve for y. Next you could plug y into dx/dt = -xy to get a seperable equation. Then solve for x & y. Be careful with your constants!

HallsofIvy
Mar30-07, 05:58 AM
My first thought was that dy/dx= -xy/-xy= 1 but that is precisely what Dick and pki15 are saying.