Basic oop Problem

Question

Hi.
I am creating a Matrix class that represents a matrix and I have a problem with OOP concept.

which way is the best for representing matrix determinant ?
1. create a property that represents matrix determinant.
2. create a member function that returns matrix determinant.
3. create a library that performs matrix operations and within it, create a function that returns a matrix determinant.

Or for example Transpose that is not as common as determinant:
1. create a member function that returns matrix transpose.
2. create a library that performs matrix operations and within it, create a function that returns a matrix transpose.

this is just an example, but I have this problem in all my OOPs.

Thanks