Formula_4711

\[x=\frac{\left(\frac{d r}{d t}, \frac{d^{2} r}{d t^{2}}, \frac{d^{3} r}{d t^{3}}\right)}{\left[\frac{d r}{d t}, \frac{d^{2} r}{d t^{2}}\right]^{2}} .\]