Notes
parallelogram identity

Parallelogram Identity

The parallelogram identity says that for vectors $\vec{u}$ and $\vec{v}$ then the length $\|\cdot\|$ satisfies:

\|\vec{u} + \vec{v}\| + \|\vec{u} - \vec{v}\| = 2 \|\vec{u}\| + 2\|\vec{v}\|

Created on November 10, 2025 22:13:05 by Andrew Stacey