Squaring a matrix and how the results matters

What is the absolute right way to square a metrix: say, A = rand (3,1) and I want absolute value

1. abs (A' *A)
2. abs (A)^2
3. abs ((A).^2)
4. abs (A .*A)
5. abs(A*A)

I know sounds sily. just try to be sure. Thanks.

Answer 1

[madhan ravi]

Array vs. Matrix operations

[az]

Thanks Ravi, I have checked those links. Now I just want to sure what it means in matlab code to square any matrix? Is it just write the matrix side by side, or transpose first one then write side by side and multiply.

If it is a matrix not array.