Ok, here's how I did it:
f := (5, (i) -> (c^2*s[i,j]^2-x[i,j]^2-y[i,j]^2-z[i,j]^2));
k := Matrix(5,1,f);
and it worked.
I have another question if you don't mind, sorry I am new with maple
I want to define a new 5x5 matrix which will be called the coefficient matrix. The matrix k by the way is the constant matrix.
The first column of the coefficient matrix will be 2 times the x matrix, the second column will be 2 times the y matrix, the third will be 2 times the z matrix, the forth will be the constant c times the s matrix, and all elements of the last and final column are equal to 1.
I think I can do it by defining each and every single element of the matrix, but I would like to know how to do it without defining each element one by one.