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- Sep 30th 2009, 12:14 AM #1

- Joined
- Jul 2008
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- Sofia, Bulgaria
- Posts
- 75

## IVP

Hello there!

I'm having some trouble with the existence and uniqueness (E&U) thms for ODEs:

Consider the IVP:

In order to use some Existence and Uniqueness(E&U) thms we need f to be Lipschitz or at least locally Lipschitz in x.

The problem is now how to prove this in special cases.

Consider the special case:

Now, assuming we want to prove existence and uniqueness we must first find the domain of f, i.e.

but I couldn't estimate f to have any Lipschitz continuity because of the singularity at 1

If we solve the equation - we find the solution to be:

which sets another domain for f: (-1,1)x(1,2]->R, apparently the more precise one.

How should I proceed in such cases?

Also, consider cases where you have to prove E&U but cannot solve the equation explicitly. Then what?!

thanks in advance!

marine