Plotting a complex exponential, exp(i*x), in 3D?

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Steven
Steven 2016-1-15
评论： Star Strider 2021-12-3
Hi, I try to plot the complex exponential, exp(i*x), in 3D. As in https://qph.is.quoracdn.net/main-qimg-b7ac15119bfa0a4840084c98da915ed8?convert_to_webp=true. Using plot or fplot, I got the warning "Imaginary parts of complex X and/or Y arguments ignored" and with ezplot: "This function has no real values".
Any suggestions on how to make such a plot in Matlab?
Thanks, Steven

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采纳的回答

Star Strider
Star Strider 2016-1-15
This approximates it:
t = linspace(0, 2.5, 250);
f = exp(2*pi*4/2.5*1i*t);
figure(1)
plot3(t, real(f), imag(f), 'LineWidth',2)
hold on
plot3(t, real(f), zeros(size(t))-1.5)
plot3(t, zeros(size(t))-2, imag(f))
hold off
grid on
axis([-1 3 -2 2 -1.5 1.5])
view([-125 30])
xlabel('Time', 'Rotation',-30)
ylabel('Real Axis', 'Rotation',10)
zlabel('Imag Axis')
If you want to add the labels, see the documetation for the text function.
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appala naidu k
appala naidu k 2021-12-3
Dear sir, Can you please help to plot the same graph for exponential decay and rise?
Star Strider
Star Strider 2021-12-3
Ran in:
Just multiply the exponential term with it.
t = linspace(0, 2.5, 250);
f = exp(2*pi*4/2.5*1i*t);
e = exp(-0.5*t);
fe = f .* e;
figure(1)
plot3(t, real(fe), imag(fe), 'LineWidth',2)
hold on
plot3(t, real(fe), zeros(size(t))-1.5)
plot3(t, zeros(size(t))-2, imag(fe))
hold off
grid on
axis([-1 3 -2 2 -1.5 1.5])
view([-125 30])
xlabel('\leftarrow Time', 'Rotation',-30)
ylabel('Real Axis', 'Rotation',10)
zlabel('Imag Axis')
Make appropriate changes to get different results.
.

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更多回答（1 个）

Steven Lord
Steven Lord 2016-1-15
x = 0:0.1:10;
yz = exp(1i*x);
plot3(x, real(yz), imag(yz))
ylabel('\Re(e^{1i*x})');
zlabel('\Im(e^{1i*x})');

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