
Determine whether A is invertible, and if so, find the inverse. (3x3)
If so, then the matrix must be invertible. There are FAR easier ways to determine whether a matrix is invertible, however. If you have learned these methods, then here are two: Put the matrix into …
what makes a function invertible? - Mathematics Stack Exchange
Aug 30, 2021 · And a function is invertible if and only if it is one-to-one and onto, i.e. the function is a bijection. This is not necessarily a definition of invertible, but it a useful and quick way of deciding if a …
What is the most efficient way to determine if a matrix is invertible?
17 Gauss-Jordan elimination can be used to determine when a matrix is invertible and can be done in polynomial (in fact, cubic) time. The same method (when you apply the opposite row operation to …
linear algebra - Prove that $A+I$ is invertible if $A$ is nilpotent ...
Prove that $A+I$ is invertible if $A$ is nilpotent [duplicate] Ask Question Asked 13 years, 7 months ago Modified 5 years, 11 months ago
Can a matrix be invertible but not diagonalizable? [duplicate]
Mar 29, 2017 · Then the associated matrix is invertible (the inverse being the rotation of $-\theta$) but is not diagonalisable, since no non-zero vector is mapped into a multiple of itself by a rotation of such …
linear algebra - Invertibility, eigenvalues and singular values ...
Jan 26, 2014 · A matrix is invertible iff its determinant is not zero. The determinant of a triangular matrix equals the product of its diagonal elements. Similar matrices have the same determinant and every …
When is $A^TA$ invertible? - Mathematics Stack Exchange
Feb 26, 2023 · Let A A be a matrix. What are some necessary/sufficient conditions for the Gram matrix ATA A T A to be invertible? This question came up when I was trying to learn about least-squares …
Why does a determinant of $0$ mean the matrix isn't invertible?
3 I always got taught that if the determinant of a matrix is $0$ then the matrix isn't invertible, but why is that? My flawed attempt at understanding things: This approaches the subject from a geometric point …
Is every injective function invertible? - Mathematics Stack Exchange
Sep 25, 2015 · A function is invertible if and only if it is bijective (i.e. both injective and surjective). Injectivity is a necessary condition for invertibility but not sufficient.
linear algebra - Is Matrix $A^2$ invertible if $A$ is invertible ...
It gets more complicated this way, but multiplying by a matrix transforms the unit hypercube into a "hyperparallelogram." The (absolute value of) the determinant gives us the "volume" scaling factor. If …