Drawing Bifurcation diagrams for a dynamical system

Phyrrus
Messages
21
Reaction score
0
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
 
Physics news on Phys.org
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.
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
Back
Top