Skip to content

Films · Mathematics · Matrices

Prof. Dr. Dirk Schieborn

Higher Mathematics 1 · Reutlingen University

Lecture film · Higher Mathematics 1

Ones, Antimatter, a Phone Number: Identity Matrix, Inverse and A · x = b

Lecture film · Higher Mathematics 1

Ones, Antimatter, a Phone Number: Identity Matrix, Inverse and A · x = b

Prof. Dr. Dirk Schieborn

Higher Mathematics 1 · Reutlingen University

The neutral element for times is the identity matrix, not the matrix full of ones. Its counterpart is the inverse: A⁻¹ · A = E. It turns the system A · x = b into the solution x = A⁻¹ · b, provided A⁻¹ exists. The phone number matrix has none.

heyprof.app/f/matrizen-inverse

More films: Signature · Prof. Dr. Dirk Schieborn

0:03
−6:27
Chapter 1 · Tables and chairs

Try the app yourself

We store questions without any link to you; selected ones appear anonymously as frequent questions.

Ones, Antimatter, a Phone Number: Identity Matrix, Inverse and A · x = b

Prof. Dr. Dirk SchiebornHigher Mathematics 1 · Reutlingen University

NewNov 4, 2026 · 6 chapters

An explainer film in six chapters, made from a real lecture: which matrix plays the role of zero and one, why the matrix full of ones is not neutral, the identity matrix, the inverse as its counterpart like matter and antimatter, the system of equations in five symbols A · x = b, the solution x = A⁻¹ · b and Gauss-Jordan elimination on the phone number matrix, which has no inverse. Pause anywhere and ask.

How a film works on heyprof

Every film here listens. Pause it, ask it questions and let it continue with your own examples.

  1. PauseTap pause or press the space bar. The film waits right at that moment.
  2. AskTap “Ask” and type what you want to know. The answer comes inside the film, with picture and voice.
  3. Steer itTell it what to show, for example “Do this with z = 2 − 3i”. The film sets up the app and works it out.
  4. Try it yourselfWhile it is paused, drag points and sliders yourself. “Continue” takes you back into the film.

Without an account: five questions per visit. With an account you can also ask by voice.

Comments