Is a matrix diagonalizable if and only if it has an eigendecomposition?
If not, can you give an example of a diagonalizable matrix which doesn't have an eigendecomposition, or vice-versa?
Is a matrix diagonalizable if and only if it has an eigendecomposition?
If not, can you give an example of a diagonalizable matrix which doesn't have an eigendecomposition, or vice-versa?
Copyright © 2021 JogjaFile Inc.
Yes. If $M$ is a $n\times n$ matrix and if there are vector $v_1,\ldots,v_n$ each of which is an eigenvector of $M$ and such that $\{v_1,\ldots,v_n\}$ is a basis of $M$, if $P$ is the $n\times n$ matrix whose columns are the $v_k$'s, then $P^{-1}MP$ is a diagonal matrix.
And if $M$ is diagonalisable and $P$ is an invertible matrix such that $P^{-1}MP$ is a diagonal matrix, then the columns of $P$ are a basis of eigenvectors of $M$.