How can I create it?

How can I create a 5x5 matrix with the following criterion: aij = 2cos(0.4(i-j)π)

Answer 1

[Star Strider]

A bit more efficiently, using meshgrid:

[i,j] = meshgrid(1:5);
a = 2*cos(0.4*(i-j)*pi);

[Taner Cokyasar]

Thank you very much. It works out great!

[Star Strider]

My pleasure!

The meshgrid function can make a number of matrix calculations easier.

Answer 2

[jgg]

Try this

 A = 2*cos(0.4.*pi.*(repmat([1:5]',1,5) - repmat([1:5],5,1)));

[Taner Cokyasar]

Thank you jgg.