Concept clusters
Related ideas that live chapters apart, pulled onto one page — every factoring technique, every way to solve a quadratic, and more.
Every way to test a subspace and find its basis
The full checklist for "is this a subspace, and if so, what's a basis and its dimension?"
10 concepts →
Every equivalent condition for invertibility
The Invertible Matrix Theorem's growing list — one true statement about A means all of them are true.
13 concepts →
Every way to compute a determinant
Cofactor expansion, row reduction, the triangular shortcut, and what the number actually means geometrically.
13 concepts →
The four fundamental subspaces, side by side
Row space, column space, null space, and left null space — where each lives, its dimension, and how they pair up.
9 concepts →
Every orthogonality tool
Dot product, projection, Gram-Schmidt, QR, and orthogonal complements — the whole orthogonality toolkit in one place.
16 concepts →