The Unit Tangent Vector T(t) (maroon), principle normal N(t) and binomal B(t) of the vector function r(t) = (t, t^2, t^3)
source: (x)
The Frenet-Serret moving frame of a space curve. A neat theorem proves that the tangent vector T, the normal vector N, and the binormal vector B = T x Nand their derivatives are related by the skew-symmetric matrix
where κ is the curvature of the space curve and τ its torsion (both of which are position-dependent but continuous) [CJH].
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