Matrix dimensions must agree.

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Daniel Rincón
Daniel Rincón 2018-2-15
评论： Star Strider 2018-2-15
Help me, Matlab print the next error.
Matrix dimensions must agree. Error in Grafica (line 4) Vt = (3./(n.*pi)).*(2-cos(-(pi.*n))-cos(pi.*n)).*sin(pi.*n.*t);
This is my code:
clc; clear all; close all
n = 0:1:10;
t = 0:0.01:10;
Vt = (3./(n.*pi)).*(2-cos(-(pi.*n))-cos(pi.*n)).*sin(pi.*n.*t);
plot (Vt)
end

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采纳的回答

Star Strider
Star Strider 2018-2-15
Yes, they must.
However you can get round that restriction by using the meshgrid function:
n = 0:1:10;
t = 0:0.01:10;
[N,T] = meshgrid(n,t);
Vt = @(n,t) (3./(n.*pi)).*(2-cos(-(pi.*n))-cos(pi.*n)).*sin(pi.*n.*t);
plot (t, Vt(N,T))
grid on
Experiment to get the result you want.

更多回答（1 个）

Jonathan Chin
Jonathan Chin 2018-2-15
n.*t
n and t don't match dimensions, when you do .* you are trying to do an element wise multiplication, since they are not the same length it gives you that error.
I think this is what you are trying to accomplish
n = [0:1:10].';
t = 0:0.01:10;
Vt = bsxfun(@times,sin(pi.*n*t),(3./(n.*pi)).*(2-cos(-(pi.*n))-cos(pi.*n)));
plot (Vt.')
I created your sine wave for every n against the array t, this creates a 11x1001 matrix, with a sin wave on each row corresponding to n
sin(pi.*n*t)
Then every column gets element wised multiplied by a 11x1 column using bsxfun(@times...)
(3./(n.*pi)).*(2-cos(-(pi.*n))-cos(pi.*n)) %11x1 column
Finally I transpose the matrix so plot can show each individual sine wave

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