Calculus 3 | 6.3: The Unit Normal Vector and |A×B| = |A||B| sin θ

Full course — free exercises, Feynman reviews, and AI-graded feedback: https://ludium.ai/courses/calculus-3 Once you can build a vector perpendicular to two others, you can turn it into a unit normal — a direction of length one. This lesson computes that unit vector and proves the magnitude formula linking the cross product to the angle between the vectors. Key concepts covered: Finding a vector orthogonal to two given vectors Normalizing to a unit normal vector Deriving |A × B| = |A||B| sin θ Connecting the algebraic and geometric forms ━━━━━━━━━━━━━━━━━━━━━━━━ SOURCE MATERIALS The source materials for this video are from    • Calculus 3 Lecture 11.4:  The Cross Product