Drawing Bifurcation diagrams for a dynamical system

Phyrrus
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1. Homework Statement [/b]
Consider the dynamical system
\frac{dx}{dt}=rx-\frac{x}{1+x}
where r>0
Draw the bifurcation diagram for this system.

Homework Equations





The Attempt at a Solution


Well fixed points occur at x=0,\frac{1}{r}-1 and x=0 is stable for 0<r<1 and unstable for all r>1
For the fixed point at \frac{1}{r}-1, however, it is stable when r-r^{2}<0

So how do I draw the non-zero bifurcation points? Thanks
 
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Phyrrus said:
1. Homework Statement [/b]
Consider the dynamical system
\frac{dx}{dt}=rx-\frac{x}{1+x}
where r>0
Draw the bifurcation diagram for this system.

Homework Equations





The Attempt at a Solution


Well fixed points occur at x=0,\frac{1}{r}-1 and x=0 is stable for 0<r<1 and unstable for all r>1
For the fixed point at \frac{1}{r}-1, however, it is stable when r-r^{2}<0

So how do I draw the non-zero bifurcation points? Thanks

Well, the bifurcation diagram is a diagram illustrating how the fixed points change as a function of the parameter. So you have two fixed points:

(0,\frac{1-r}{r})

So those change as a function of r right? Got two until r=1, got one there, then two again when r>1. Can you not just plot those two fixed points as a function of r? You can do that.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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