[Help-gsl] Solving a First Order ODE system using GSL

[Earl, Joseph]

Hi,

I am trying to solve a first-order ODE of the form

x' = sqrt(1/3x - k + lx^2)

using the GSL C++ library, where k and l are constants for a particular 
solution.

I have no problem at all using GSL to solve 2nd order (such as x'' = -x) and 
higher ODEs, something is just confusing about the first order equations and 
how to put them into the required form.
The Jacobian doesn't seem to make much sense with a 1st order ODE.

Also the current documentation is pretty poor - there is only one example of a 
2nd order ODE which is repeated all over the net. So if anyone wants to add a 
1st order example to the help docs I'm sure that would be of some use to others 
(and me!) in the future.

Any help would be much appreciated (if you feel like writing out a full working 
example that would be awesome).

Regards,
Joseph Earl
Imperial College London