Lesson 1.5 · 5 of 25 lessons

Inverse matrices

Connect row and column pictures of a system to elimination, LU, and inverse matrices.

Open the interactive animation

01 · Story

What to verify in this scene

Follow the explanations and operations, then identify the mathematical evidence that remains in the final scene.

  1. 01

    When A moves space, x moves from (1, 1) to (3, 2)

  2. 02

    First apply A to see the forward transformation

  3. 03

    Now apply inverse matrix B to undo A

  4. 04

    x returned to (1, 1)
    An inverse matrix cancels the original transformation

02 · Notebook

The runnable notebook

This source creates the mathematical objects and controls the order of operations and animation. Read it here, then play the same scene yourself.

2d
zoom 9/10
grid off
relative-grid on
coordinates on

2 1  #A
1 1

1 -1  #B
-1 2

1, 1  #x@
// When {{A}} moves space, {{x}} moves from `(1, 1)` to `(3, 2)`
checkpoint Inverse matrices · 1

// First apply {{A}} to see the forward transformation
A
checkpoint Inverse matrices · 2

// Now apply inverse matrix {{B}} to undo {{A}}
B
// {{x}} returned to `(1, 1)`\nAn inverse matrix **cancels the original transformation**
focus x
Open the interactive animation

03 · Unit 1

Lessons in this unit

Matrices & Gaussian elimination — Connect row and column pictures of a system to elimination, LU, and inverse matrices.

  1. 1.1Two views of a system
  2. 1.2Gaussian elimination
  3. 1.3Matrix columns
  4. 1.4LU factorization
  5. 1.5Inverse matrices