Determinants and inverses
Objective. Compute determinants and use them to test invertibility.
- 1. Learn
- 2. Worked example
- 3. Practice
- 4. Feedback
- 5. Continue
Learn: the key idea
A square matrix is invertible exactly when its determinant is non-zero; the determinant is the scale factor of the transformation.
Worked example
Find the determinant of [[3, 1], [2, 4]].
- 1det = ad − bc.
- 23×4 − 1×2 = 12 − 2.
Answer: 10
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