Cannot understand about this

Below is my code:

When I proceed this, I can get 2 lines, one of which I cannot understand.

1st one is an expected, diverging line to negative infinity, but the other I get is y=x+1 line...

Where is it from?? I cannot figure it out :(

Moreover if I add plot of z11 as well using plot(z11, '-k.') and hold on,

z11 plot also follows the y=x+1 line, while it never does alone!!!! OMG WHY IS IT

a=2.95; x11=0.5; x12=-0.001; i=0;
z11=[i x11];  z12=[i x12];

while i<50
    y11=f(a,x11); y12=f(a,x12); 
    x11=y11; x12=y12; i=i+1;
    z11=[z11; [i y11]];  z12=[z12; [i y12]];
end
figure(1)
title('alpha=2.95')
subplot(2,2,1)

plot(z12,':rd')
axis([0 50 -1 1])

function f=f(a,x); f=a*x*(1-x); end

[Sriram Tadavarty]

You observe as such because you plot both i and the actual value in z11 and z12. Implies z11 and z12 are M x 2 matrix. Plot the second column only and it would provide the expected results. Try plot(z12(:,2), ':rd')

[Byeongchan Min]

wow it worked thx!!! I think it'll take longer to understand it thoroughly though :D

[Sriram Tadavarty]

Glad that it helped.

I will place the same in answer

Answer 1

[Sriram Tadavarty]

Hi Byeongchan,

This observation is becuase the variable i and actual value in z11 and z12 are plotted. Since the effect values of z11 and z12 are a matrix of M x 2. Both the columns of them are plotted.

To have the proper plot, use the second colmn itself and it would provide expected results.

Try plot(z12(:,2), ':rd')

For more details, look at plot.

Hope this helps.

Thanking you.

Regards,

Sriram