Stage 29 · Spatial Vectors & Solid Geometry

29.1.6 The Dot Product of Spatial Vectors

29.1 From Plane Vectors into Space — Spatial Vectors and Linear Operations

Point 6 of 6

29.1.6 The Dot Product of Spatial Vectors

Core idea

The smaller the angle between two arrows the more "in sync" they are, and a·b=|a||b|cosθ measures just how in sync.

Module goal. Carry the familiar arrow of a plane vector into three dimensions, build up addition, subtraction, scalar multiplication, and tests for collinear and coplanar vectors in space, picking up where the last stage's feel for solid shapes left off.
eastmath.com · 29.1 From Plane Vectors into Space — Spatial Vectors and Linear Operations · 29.1.6 The Dot Product of Spatial Vectors