matrix columns and rows manipulating with loop

n=6; %which is variable, the number of vector's dimension. 
i=1:(n-3);
u=cos(i-3);
u=u(:);
jn=(2*cos(u(i)));

% I need to create below arrays with loop w.r.t. the "n" and "jn";

column_1=[0;0;0;jn(1);0;0];   %number of columns is equal (n-3)
column_2=[0;0;0;0;jn(2);0];
column_3=[0;0;0;0;0;jn(3)];

Answer 1

[Guillaume]

No need for loop. You're also better off keeping your 3 columns as one matrix rather than making individually numbered variables.

 m = [zeros(n-3, 3); diag(jn)]