MATLAB: What should I do? In an assignment A(:) = B, the number of elements in A and B must be the same.

Question

%%it says that error is in the x(i+1) and y(i+1)
while norm(J) > e 
    I = [x(i),y(i)]';
    syms h; % Step size
    g = subs(f, [X,Y], [x(i)+S(1)*h,y(i)+h*S(2)]);
    dg_dh = diff(g,h);
    h = solve(dg_dh, h); % Optimal Step Length
    x(i+1) = I(1)+h*S(1); % Updated x value
    y(i+1) = I(2)+h*S(2); % Updated y value
    i = i+1;
    J = [subs(df_dx,[X,Y], [x(i),y(i)]) subs(df_dy, [X,Y], [x(i),y(i)])]; % Updated Gradient
    S = -(J); % New Search Direction
end

Answer 1

My solution