Ok Guys now im Having some more problems.

I have managed to make the sigmoid curve required, however, I want the curves to look like the ones on this website

Interesting Facts about Population Growth Mathematical Models
as you can see here even though they use the same values as me the curve is different.

This also allows them to look at multiple fixed point values (something i need to do)

simply by changing their value of r (my value of $\displaystyle \lambda$

He calls his equation the Verhulst equation, but its a difference equation and mine is a differential version of it, however essentially they look pretty much the same to me.

The sigmoid curves that I am achieving always plateau at the value of K i am using, where as the ones he draws pleateau below K, depending on the value of r he uses.

How can I change mine so that I can get these multiple fixed points/declining population to 0, simply by changing my value for $\displaystyle \lambda$

Thanks again guys.

Tom