MATLAB: The following error occurred converting from sym to double: Unable to convert expression into double array.

diff()doubleMATLABsymbolicsyntax

R = 35.9; L = 3.98; C = 0.000360; P = ceil(R/(2*L));
M = ceil(sqrt( (1/(L*C)) - ( (R^2)/ (4*(L^2)) )));
phi_values = zeros(101, 2);
for ix = 1:101
    phi_values(ix, 1) = cos(M * t); 
end
I have no idea what is the problem

Best Answer

t is a symbolic variable instead it has to have doubles (numbers):
R = 35.9; L = 3.98; C = 0.000360; P = ceil(R/(2*L));
M = ceil(sqrt( (1/(L*C)) - ( (R^2)/ (4*(L^2)) )));
phi_values = zeros(101, 2);
t=linspace(0,pi,101);   % define t this way
for ix = 1:numel(t)
    phi_values(ix, 1) = cos(M * t(ix)); 
end
Without loop the same result can be obtained:
R = 35.9; L = 3.98; C = 0.000360; P = ceil(R/(2*L));
M = ceil(sqrt( (1/(L*C)) - ( (R^2)/ (4*(L^2)) )));
t=linspace(0,pi,101);
phi_values = (cos(M .* t)).';
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