Glossary math Term Page
Normal Equation
The equation encoding the least-squares condition
Core Idea
The normal equation is the algebraic form of the least-squares condition. The standard expression A^T A x = A^T b comes from requiring the residual to be orthogonal to the column space of A.
Role In This Blog
In Mathbong, the normal equation serves as the algebraic bridge between projection geometry and linear regression fitting.