How can I add values to an empty vector from a for loop?

y=0;

for l=1:5
    y = y+(4.*l*(1/20).^2.*sin(pi*(1/20))*sin(pi*(1/20)))./(pi^2.*(l.^2-(1/20)^2).*(l.^2-(1/20)^2));
    disp(y);

end

Answer 1

[Damien]

Hello Penglu,

I'm not sure of what you want to do exactly but you can try this code:

y=0;
for l=1:5
y(l) = y(1)+(4.*l*(1/20).^2.*sin(pi*(1/20))*sin(pi*(1/20)))./(pi^2.*(l.^2-(1/20)^2).*(l.^2-(1/20)^2));
end
disp(y);

More generally use this:

for i = 1:5
y(i)=2*i;
end

[Stephen23]

Note that preallocation is recommended instead of expanding arrays inside loops:

https://www.mathworks.com/help/matlab/matlab_prog/preallocating-arrays.html

https://www.mathworks.com/help/matlab/matlab_prog/techniques-for-improving-performance.html