 Curvature and torsion

For unit speed, $\kappa =|T^{\prime }|$ and $\tau =-B^{\prime }\cdot N$. Generally $\kappa =|r^{\prime }\times r^{\prime \prime }|/|r^{\prime }{|}^3$ and $\tau =\det (r^{\prime },r^{\prime \prime },r^{\prime \prime \prime })/|r^{\prime }\times r^{\prime \prime }{|}^2$.