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These are answers submitted by bongiman

I don't know what happened to my previous post so let me try that again...

 I edited the code very slightly:

> with(plots):
   Aplot:= implicitplot(max(x^2+(y+2)^2-4,1-x^2 - (y+2)^2) <= 0, x = -2 ..2, y = -4 .. 0,   
   Bplot:= implicitplot((abs(argument(x+(2+y)*I))-Pi/3),
     x=-2..2,y=-4..0, grid=[100,100],filledregions=true,gridrefine=3,crossingrefine=3,
     transparency=1/2, coloring=[green,white]):

Now how do i only plot the bit where A & B intersect, i.e. the bit of the closed annulus within B?



I've bookmarked this page for future reference! It's these kind of helpful hints which make one able to appreciate good coding. I wish i had more time to play around in Maple!

Thanks again for your help


Why not! If it doesn't help me it's sure to help someone else who reads this post.

Thanks a mill for your help Acer. Legend!



Just to confuse things i forgot my password when i swithched to Google chrome so signed in with a new ID. I'd since remebered it so have switched back but was still logged in on the other browser.....sorry to bring confusion into the mix.

I was so close but so far! :)

Apologies, problem solved!


I think i must've put a space between the ln and the rest of the equation for eqa y1!

Problem solved!!


I'm having problems pasting into Mapleprimes for some reason. Let me try this again!!

>N:= 20000

>xa:=-10:    ya:=-10:

>xb:=10:    yb:=10:

>x0:=0.1       y:=0:

>alpha:=0.4:   Beta:=1.2


>x1:= exp(y0);

>y1:= ln(x0^alpha))-y0^2+Beta;


>end proc:

>from 1 to 99 do H() end do:

>orbit:= [seq(H(),k=100..N)]:

>plots[pointplot](orbit,symbol=point, view=[xa..xb,ya..yb], colour=blck,title=sprintf("StrangeAttractor:alpha=%alpha,Beta=%Beta",alpha,Beta));

Thanks again.



Doug, yes that is brilliant. You have been an excellent help. I think i was chasing a red herring by trying to convert to cartesian.

I predicted that the fixed points occured at r = 0,1,2,3,.... and that Pi*r is unstable when r is even and stable when r is odd. Which is what your phase portrait confirms. Am i correct in saying that this implies that in the xy-plane there will be a unstable spiral at the origin and a stable limit cycle for all odd values of r where r=1,3,5,... and similarly a stable limit cycle for all even values of r, where r=2,4,6,...

Your phase portrait is brilliant. I'm not nearly familiar enough with Maple to come up with such things. Thanks for all your help.





Of i remeber!

Thanks a million Robert

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