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Topic: Integration with variable limits
Replies: 17   Last Post: Aug 20, 2013 10:20 AM

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Sanaa

Posts: 164
Registered: 3/20/12
Re: Integration with variable limits
Posted: Jul 25, 2013 4:58 PM
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"Torsten" wrote in message <ksrcel$2k$1@newscl01ah.mathworks.com>...
> "Sanaa" wrote in message <ksrbia$r0l$1@newscl01ah.mathworks.com>...
> > Hi all,
> > How to integrate a function within a loop and the limits of integration are variables?
> > For instance, y(i)*(1-y(i)) is the function I wish to integrate from 0.25*i to t where
> > t \in (0.25*i, 0.25*(i+1)).
> > Any help is really appreciated.
> > Sanaa Moussa

>
> I think y(i)*(1-y(i)) is just a real number, not a function, isn't it ?
>
> Best wishes
> Torsten.


Thanks for replying. You are right, but I mean the function is y*(1-y) which I want to put it into a loop
My code is
itermax=300;min=itermax-9;% That is we plot from 291:300 i.e. 10 values of x only.
r=0.25;
for rho=0:0.001:4
%x0=0.1;
x(1)=0.1;
for i=1:itermax-1
%t=linspace(i*r,(i+1)*r,itermax)
y(i+1)=x(i);
x(i+1)=x(i)+ rho*int(y(i)*(1-y(i)),i*r,(i+1)*r);
end
%fix(y)
plot(rho*ones(10),x(min:itermax),'b.','linewidth',0.1)
hold on
end
fsize=15;
xlabel('\rho','FontSize',fsize)
ylabel('\itx','FontSize',fsize)
%title('r=0.25, \alpha=1','FontSize',fsize)
hold off
% print(gcf, '-djpeg', '-zbuffer', 'bif.png');

I get the error
Function 'int' is not defined for values of class 'double'.
what does this mean and how to fix it please?
Many thanks in advance.



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