i want to find k for different values of w, k will be obtained from the determinant of the matrix ,this is a sample my actual code is 8 by 8 matrix ,please help

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Rosalinda 2023-11-4

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https://ww2.mathworks.cn/matlabcentral/answers/2042802-i-want-to-find-k-for-different-values-of-w-k-will-be-obtained-from-the-determinant-of-the-matrix-t

评论： Rosalinda 2023-11-4

%finding k for different values of w
syms k
c44=44;
i=sqrt(-1);
for w=1:3
s(j)=c44*exp(k)*w(j);
p(j)=c44/w(j);
q(j)=c44+w(j)*i/k^2;
A=[c44*s(j) 2;p(j) q(j)];
z=det(A);
y=vpasolve(z,k);
end
Array indices must be positive integers or logical values.

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Walter Roberson 2023-11-4

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You are looping for w but you are using j as your index. The default value for the variable j is sqrt(-1) so you are trying to index by the imaginary constant.

Note also that when you for w=1:3 that at any point inside the loop, w will be a scalar. But your loop has w(j) inside the loop whcih is an attempt to index the scalar by j . In context, with those assignments, the only way those assignments could work is if j is either 1 or true or false or []

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Walter Roberson 2023-11-4

you do not ask it to display answers. Also you overwrite all of y each iteration so that at the end of the loop y would hold only the result from the final iteration.

Rosalinda 2023-11-4