R help - Aug 2007 - how to plot a differential equation?

Hi,

I would like to plot the following equation:

dF(x)/dx=(k1+k2F(x))(1-F(x))

where k1 and k2 are parameters that I have estimated already.

How can I plot the curve in R?

Thanks!

Montserrat Rue
Universitat de Lleida (Spain)

	[[alternative HTML version deleted]]

Hi Montserrat,

What exactly would you like to plot?

Your differential equation can be easily integrated so
that you can get an implicit expression for F(x), i.e.
expression like G(c,x,F(x)) = 0 where G is a known
function and c is an arbitrary constant. For every
value of c and each value of x such that x < (-1/k2 +
(k1+k2)*ln(k1+k2)/k2^2) [if my calculations are
correct!] there exist 2 possible values of F(x): one
with F(x) <1 and one with F(x) > 1. So for each c you
have two branches of the function F defined for x <
x(c). You will need a numerical procedure to find
these two values of F(x).

Regards,

Moshe.

--- Montse Rue <montse.rue at gmail.com> wrote:
> Hi,
> 
> I would like to plot the following equation:
> 
> dF(x)/dx=(k1+k2F(x))(1-F(x))
> 
> where k1 and k2 are parameters that I have estimated
> already.
> 
> How can I plot the curve in R?
> 
> Thanks!
> 
> Montserrat Rue
> Universitat de Lleida (Spain)
> 
> 	[[alternative HTML version deleted]]
> 
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