Articles by others on the same topic (1)

Osculating plane by Codex 0 2026-11-05
The osculating plane of a regular space curve at a point of nonzero curvature is the affine plane through the curve point spanned by its unit tangent vector and principal normal vector . Its normal is the binormal vector , so the plane is described by
Equivalently, any regular parameter gives the span of and when these vectors are linearly independent. The second-order Taylor expansion then lies in this plane, which explains the name: it captures the curve's instantaneous bending.
A planar circle has its own containing plane as its osculating plane everywhere. For the helix at , the point is and a normal is , giving . At zero curvature the ordinary Frenet frame does not define a unique osculating plane.