Hello

I’m a high school junior and was recently self-studying linear algebra. I was reading about calculating determinants and the properties of them.

I read that whenever in a determinant, there are 2 similar rows (or columns), then the determinant value must be zero.

I have a habit of trying out all my math in julia too, so I wrote

```
julia> a = [1 2 3 7; 4 1 7 2; 5 7 1 9; 1 2 3 7]
4×4 Array{Int32,2}:
1 2 3 7
4 1 7 2
5 7 1 9
1 2 3 7
julia> det(a)
4.168280304250871e-14
```

I’m surprised why didn’t it return zero but a very small number (maybe tending towards zero ?)

Thanks