[solveit]

Stack the vectors up so it's a matrix and take the determinant. The sign tells you which one it is.

[gowld]

No, it does not. The determinant tells you whether two bases have the same or different handedness, not which one is "left" or "right".

[lanstin]

It's 2 cosets, one is arbitrarily left handed and the other arbitrarily right handed. If you are in an orientable space :) if not, then there's no global concept of left or right. a

[fredilo]

Formulated differently, you cannot determine left- and right-handedness but you can determine same-handedness.