matrix, Step by Step Linear Algebra for the TI-84 Plus CE






GitHub Repository, Releases, Download at Cemetech


matrix is a linear algebra program for the TI-84 Plus CE graphing calculator. It automates the mechanical parts of linear algebra, such as determinants, row reduction, inverses, Cramer's rule, and more, while showing every step so you can follow along.

Steps are rendered as typeset LaTeX directly, powered by bundled libtexce.

Linear algebra courses require long repetitive calculations by hand. matrix does the calculations for you and still shows the full process.

• Enter integer matrices up to 6x6 with a spreadsheet style editor.
  
• Pick an operation from a menu and get results instantly.
  
• Page through step by step LaTeX explanations of the full computation.
  
• See exact rational arithmetic as fractions.
  
• Run natively on TI-84 Plus CE hardware.
  

Features

Matrix Operations

• Add / Subtract, element-wise matrix addition and subtraction.
  
• Multiply, full matrix multiplication with dot product steps.
  
• Transpose, transpose of any matrix.
  
• Determinant, cofactor expansion with smart row or column selection.
  
• Inverse, Gauss-Jordan elimination on the augmented matrix [A | I].
  
• REF / RREF, Row Echelon Form and Reduced Row Echelon Form.
  
• Cramer's Rule, solve Ax = b with per-delta step breakdowns.
  
• Minor / Cofactor, compute M_ij and C_ij for any element.
  
• Minor Matrix, full matrix of minors.
  

Vector Operations

• Dot Product, scalar dot product of two vectors.
  
• Cross Product, 3D cross product.
  
• Projection, orthogonal projection of u onto v, plus the orthogonal complement.
  

Subspace Analysis

• Column Space Basis, basis for Col(A) via pivot columns.
  
• Row Space Basis, basis for Row(A) via non-zero rows of RREF.
  
• Null Space Basis, basis for Null(A) from free variables.
  
• Left Null Space Basis, basis for Null(A^T).
  
• Span Test, test whether a vector is in the span of a set or R^m.
  
• Independence Test, test whether a set of vectors is linearly independent.
  
• Solve via RREF, solve a linear system with row reduction.
  

Step by Step Explanations

Every operation generates a detailed explanation.

• Move forward and backward through steps with left and right arrow keys.
  
• Each step shows a plain text caption and a rendered LaTeX matrix or expression.
  
• Multi-part operations (for example Cramer's rule) include sub-menus for each determinant.
  

Getting Started

Requirements

• A TI-84 Plus CE or TI-84 Plus CE Python Edition.
  
• A USB cable.
  
• A transfer tool, TI Connect CE (Windows) or webtilp (macOS/Linux/Chromebooks).
  

Installation

1. Download the latest MATRIX.8xp from Releases.
   
2. Connect your calculator over USB.
   
3. Get clibs from tiny.cc/clibs.
   
4. If your OS is above 5.4, install arTIfiCE to launch third-party programs.
   
5. Transfer MATRIX.8xp, required fonts, clibs, and arTIfiCE. Choose ARCHIVE when prompted.
   

Quick Start

1. From the main menu, choose Matrices, then Edit A.
   
2. Set dimensions (for example 3x3), then press ENTER.
   
3. Move cell to cell with arrows, press ENTER to edit and confirm.
   
4. Press CLEAR to finish editing, then go to Operations, Determinant.
   
5. Select slot A, the determinant is computed and shown.
   
6. Press a key to open the full step by step cofactor expansion in LaTeX.
   
7. Use left and right arrows to page steps, use CLEAR to go back.
   

How to Use

Navigation

• UP / DOWN, scroll menus and matrix rows.
  
• LEFT / RIGHT, move matrix columns, page through steps.
  
• ENTER, select menu item, confirm input, edit cell.
  
• CLEAR, go back one screen.
  
• DEL, set current cell to 0 in the editor.
  
• 2nd, finish matrix editing.
  

Editing Matrices

• Dimensions are selected with an arrow key selector (1 to 6 rows, 1 to 6 columns).
  
• The grid editor shows all cells at once.
  
• Cell values are entered in a footer input line, including negatives and multi-digit values.
  
• Resizing a matrix clears its contents.
  

Step Viewer

• Steps are rendered one at a time in LaTeX, each page includes a caption and typeset math.
  
• A step counter (for example 3/7) shows your position.
  
• Complex operations expose sub-computations in sub-menus.
  

Contributing

See CONTRIBUTING.md for technical overview, project structure, build instructions, and testing.

That's quite an impressive project to come out of nowhere! I'll be sure to try this out when I get the chance 🙂 Does it support matrix dimensions such as 2*4?

Thank you, and yes, matrices up to 6x6 are supported, square or not