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Topic: Legend won't pick up on plot colors
Replies: 3   Last Post: Mar 14, 2013 1:55 AM

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Nasser Abbasi

Posts: 5,606
Registered: 2/7/05
Re: Legend won't pick up on plot colors
Posted: Mar 14, 2013 1:33 AM
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On 3/13/2013 8:33 PM, trbone76 wrote:
> t0=0;
> tf=0.02;
> h=0.001;
> y0=[1;4];
> f=@(t,y) [-8003*y(1)+1999*y(2);23988*y(1)-6004*y(2)];
> f_exact=@(t,y) [exp(-7*t);4*exp(-7*t)];
>
> t = t0:h:tf;
>
> y_exact = zeros(length(y0),length(t));
> for j = 1:length(t)
> y_exact(:,j) = f_exact(t(j));
> end
>
> y = zeros(length(y0),length(t));
> y(:,1) = y0;
> for i = 1:length(t)-1
> y(:,i+1) = y(:,i) + h*f(t(i),y(:,i));
> end
>
> plot(t,y_exact,'b',t,y,'r')
> legend('Exact Solution','Euler Approximation');
> grid on
> axis([t0 tf -1 5])


You really need to have same legend as plots.

You have 4 plots and only 2 legends. (your y's are 2 rows
each).

Change you plot command to this and it will work:

plot(t,y(1,:),'b',t,y(1,:),'r');


--Nasser



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