In the context of tensor calculus, by using Serret-Frenet formula or otherwise,
how to prove that
$\tau^2=\displaystyle\frac{r'''^2}{k^2}-k^2-(\frac{k'}{k})^2$
where $\tau$ and $k$ represent respectively torsion and curvature.
In the context of tensor calculus, by using Serret-Frenet formula or otherwise,
how to prove that
$\tau^2=\displaystyle\frac{r'''^2}{k^2}-k^2-(\frac{k'}{k})^2$
where $\tau$ and $k$ represent respectively torsion and curvature.