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**yago.dorea****Member**- Registered: 2012-09-09
- Posts: 6

I want to solve the following ODE:

(1 + t²)y' = ty(1 + y²) where y = y(t).

If I try to solve it by separation, I get complex roots, but I'm not trained yet to deal with them.

What should I do?

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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 7,764

hi yago.dorea

Welcome to the forum.

Separation, the partial fractions for y and 'function of a function' for t.

I'm getting

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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**yago.dorea****Member**- Registered: 2012-09-09
- Posts: 6

How exactly do you separate?

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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 7,764

hi

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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**yago.dorea****Member**- Registered: 2012-09-09
- Posts: 6

Okay, but the result of this equation is that y(t) is a complex function ( y² = sqrt(-(t²+1))/t ). Can this be the right answer?

*Last edited by yago.dorea (2012-10-09 19:25:23)*

Live long and prosper.

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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 7,764

Go back to

Let's say 2C = lnA

Now you should have been given values of y and t to enable you to work out A.

For what follows I'm going to assume lnA = 1

So it does seem to give that function.

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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