Help me plot grafic pls.
6 views (last 30 days)
Show older comments
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1203578/image.png)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1203583/image.png)
I want to plot the above graph according to the above equation. Can you help ?
0 Comments
Answers (2)
William Rose
on 22 Nov 2022
Yoiur foumula includes an infinite sum. Do a finite sum and see if it converges after 10 or 20 or 30 terms. When I do it, I see that the solution with n=20 is almost identical to the solution with n=10, and the solution with n=30 is not visibly differnt from the solution with n=20.
All three solutions look very different from the plot you posted. Perhaps I made a msitake. Check my work. Are you sure the plot you provided is a plot of the analytical solution using the equation shown? Why does R=1.04 appear in the plot, but not in the analytical solution?
x=0.5;
t=0:.0026:0.0702; %time vector
u1=zeros(size(t)); u2=u1; u3=u1; %allocate u
n1=1:10;
n2=1:20;
n3=1:30;
for i=1:length(t)
u=(0.63/pi^2)*(1./(n1.*n1)).*sin(n1*pi/1.5).*cos(100*n1*pi*t(i)/1.5).*sin(n1*pi*x/1.5);
u1(i)=sum(u);
u=(0.63/pi^2)*(1./(n2.*n2)).*sin(n2*pi/1.5).*cos(100*n2*pi*t(i)/1.5).*sin(n2*pi*x/1.5);
u2(i)=sum(u);
u=(0.63/pi^2)*(1./(n3.*n3)).*sin(n3*pi/1.5).*cos(100*n3*pi*t(i)/1.5).*sin(n3*pi*x/1.5);
u3(i)=sum(u);
end
plot(t,u1,'-r.',t,u2,'-g.',t,u3,'-b.');
legend('n=10','n=20','n=30'); grid on; xlabel('Time'); ylabel('u')
Try it.
0 Comments
David Hill
on 22 Nov 2022
What is R? The solution does not match your graph.
x=.5;
t=0:.0025:.07;
n=(1:100)';
H=1./n.^2.*sin(n*pi/1.5).*cos(100*n*pi/1.5.*t).*sin(n*pi/1.5*x);
u=0.63/(pi)^2*sum(H);
plot(t,u,'*-')
0 Comments
See Also
Categories
Find more on Line Plots in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!