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Topic: How I make odefun for this odes(see message) in MatLab
Replies: 1   Last Post: Dec 10, 2012 2:52 AM

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Torsten Hennig

Posts: 2,419
Registered: 12/6/04
Re: How I make odefun for this odes(see message) in MatLab
Posted: Dec 10, 2012 2:52 AM
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> How I make odefun for this odes {dy/dx = du/dx +
> y(x), du/dx = dy/dx + u(x)} in MatLab?
> dy/dx = du/dx + y(x)
> du/dx = dy/dx + u(x)

Your ode system can be rewritten as

dy/dx - du/dx = y(x)
dy/dx - du/dx = -u(x)

Thus it only has a solution if y(x) = -u(x).
Inserting gives

2*dy/dx = y(x)

which has solution

y(x) = a*exp(0.5*x)

where a is an arbitrary constant.

From y(x) = -u(x) you get u(x) = -a*exp(0.5*x).

Best wishes

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