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The Matrix BookA Visual Guide to Matrices

Intuitive linear algebra for readers who want to see what matrices mean, not just compute with them.

Stylized matrix book cover

Why this edition works as a book

This build is designed to feel closer to a digital textbook than a plain markdown dump. The site has persistent navigation, chapter-by-chapter flow, book typography, local search, math rendering, and Mermaid diagrams rendered inline.

The core teaching approach stays consistent throughout:

  • intuition before formalism
  • concrete worked examples before abstraction
  • geometric interpretation wherever it sharpens understanding
  • recaps and exercises to consolidate each chapter

Reading paths

  • New to the topic: read from Chapter 1 through Chapter 8 in order.
  • Interested in geometry and dynamics: focus on Chapters 5, 6, 10, 11, 12, and 16.
  • Interested in data and machine learning: focus on Chapters 8, 9, 10, 13, 15, and 17.
  • Want a fast refresher: read Chapter 18 and Appendix B first, then dip into chapters as needed.

Attribution

Authors: John Olafenwa and GPT-5.4

This book was created for personal learning by John Olafenwa, using the OpenAI Codex App powered by GPT-5.4.

For a citation-ready version, see the Attribution page.

Table of contents

Book Part

Part I. Seeing Matrices

Build the language of matrices from intuition, shape, operations, and systems.

  1. Chapter 1. Why Matrices Matter

    Why matrices appear everywhere, and how to think of them as tables, machines, and maps.

  2. Chapter 2. Seeing Matrices

    Rows, columns, dimensions, vectors, and the different ways a matrix can be read.

  3. Chapter 3. Matrix Operations

    Addition, scaling, multiplication, transpose, and the meaning behind the rules.

  4. Chapter 4. Solving Systems

    Gaussian elimination, pivots, augmented matrices, and the logic of solving many equations at once.

Book Part

Part II. Geometry and Structure

Move from calculation into geometry, structure, invertibility, and the hidden shape inside matrices.

  1. Chapter 5. Linear Transformations and Geometry

    Stretching, rotating, shearing, and understanding matrices through movement in space.

  2. Chapter 6. Determinants

    Signed area, signed volume, orientation, invertibility, and why determinants measure scaling.

  3. Chapter 7. Inverses and Factorizations

    Undoing transformations, solving efficiently, and breaking matrices into simpler pieces.

  4. Chapter 8. Subspaces, Basis, and Rank

    Span, independence, column space, null space, dimension, and rank.

Book Part

Part III. Direction, Approximation, and Decomposition

Study invariant directions, approximation, and the decompositions that organize complex linear behavior.

  1. Chapter 9. Orthogonality and Least Squares

    Dot products, projections, orthonormal bases, and fitting imperfect data.

  2. Chapter 10. Eigenvalues and Eigenvectors

    Invariant directions, scaling factors, and why some directions matter more than others.

  3. Chapter 11. Diagonalization and Dynamics

    Repeated matrix action, powers of matrices, and discrete-time systems.

  4. Chapter 12. Symmetric Matrices and Quadratic Forms

    Energy, curvature, ellipses, principal axes, and why symmetry simplifies everything.

  5. Chapter 13. Singular Value Decomposition

    Rotate, stretch, rotate again: the geometry and power of SVD.

Book Part

Part IV. Applications and Computation

Apply matrix thinking to networks, data, continuous systems, and real computational constraints.

  1. Chapter 14. Matrices in Networks and Markov Chains

    Graphs, transitions, walks, steady states, and long-run behavior.

  2. Chapter 15. Matrices in Data, Images, and Machine Learning

    Datasets, features, image grids, embeddings, covariance intuition, and practical modeling ideas.

  3. Chapter 16. Differential Equations and Continuous Systems

    Coupled systems, matrix exponentials, and continuous-time dynamics.

  4. Chapter 17. Numerical Linear Algebra

    Floating point arithmetic, conditioning, stability, and the computational reality of matrix problems.

  5. Chapter 18. Cheat Sheet and Next Steps

    A synthesis chapter with concept links, pitfalls, and directions for further study.

Reference

Appendices

Practice support and quick-reference material for revision and review.

Created for personal learning by John Olafenwa using the OpenAI Codex App powered by GPT-5.4.