Multiple variables in for loop

Hello, I want to get each error value(E) for 3 a's. How can I do it ? (I don't know how to pre-allocate)

a=[11,51,101]
Toplam=0
x=pi/3
for (k=0:a)
    x=(((-1)^k*(x))^((2*k)+1))/factorial((2*k)+1)
    Toplam=Toplam+x
    W=Toplam+x
    E(a)=abs(W-0.86602540378444)
    H(a)=E(a)/(0.866)      
end

Answer 1

[Birdman]

Something like this?

a=[11,51,101] 
%preallocation
E=zeros(1,numel(a));
H=zeros(1,numel(a));
Toplam=0 
x=pi/3 
for (k=1:numel(a)) 
x=(((-1)^(k-1)*(x))^((2*(k-1))+1))/factorial((2*(k-1))+1) 
Toplam=Toplam+x 
W=Toplam+x 
E(k)=abs(W-0.86602540378444) 
H(k)=E(k)/(0.866) 
end

Answer 2

[Aditya Deshpande]

NOTE: MATLAB arrays starts with index of 1. I think you meant to do the following:

a=[11,51,101];
Toplam=0;
x=pi/3;
H = zeros(3,1); E=zeros(3,1);
for i=1:length(a)
    k=a(i);
    x=(((-1)^k*(x))^((2*k)+1))/factorial((2*k)+1);
    Toplam=Toplam+x;
    W=Toplam+x;
    E(i)=abs(W-0.86602540378444);
    H(i)=E(i)/(0.866);
end