MATLAB: How to make a serie

MATLABsumsum function

Hi, i need to write a sum of serie :

with b_k= (k+1)^2-(k)^2 and u^(m-k) is the numerical solution approximation u(x,t_m-k) for k=1,…m-1 and m=1,….,20

for m=1:20
syms k u
b(k)=(k+1)^2-k^2;
F=symsum((b(k)-b(k+1))*u(:,m-k),k,1,m-1)
end
F

but i get error

Necessary I need u(:,m-k)

Please help me

Best Answer

It is never possible to use a symbolic variable as an index in MATLAB.

You need to create a definite list of values and sum() the list. Or loop adding on to a total.

Note by the way that

and so b(k) - b(k+1) = (2*k+1) - (2*(k+1)+1) = -2

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MATLAB: How to compute the sum term

alpha = 0.6;
U(1)=1;%you need to specify U(1) and U(2)
U(2)=.5;
S=2^(1-alpha)*(U(1)-U(2));
U(3)=(U(2)+S)/2;
for n=3:50
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MATLAB: I am getting an error while executing a short code to update a matrix, In an assignment A(I) = B, the number of elements in B and I must be the same. Er

Not sure if this is what you are trying to do, but I am taking Torsten's approach.

A=[0 1 1 1 ;0 0 0 1 ;0 1 0 1 ;0 0 0 0]; 
N=4; 
C=2; 
rho=0.1; 
B=zeros(N,C,N); 
a=[1 0;0 1;1 1;0 1];
for k=1:N-1 
  B(:,:,k+1) = B(:,:,k) + (0.5 * rho* a); 
end

Best Answer

Related Solutions

MATLAB: How to compute the sum term

MATLAB: I am getting an error while executing a short code to update a matrix, In an assignment A(I) = B, the number of elements in B and I must be the same. Er

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