A friend of mine sent me this document so I can learn how to get eigenvalues and eigenvectors in mathematica the long way, this for a homework. I open the document and everything is fine, but when I run the inputs in my computer it gives me a totally different output, it even changes the DiagonalizableMatrix from true to false. Does this has to do with the operating system? is it my computer? I've tried opening it with the browser version (chrome and edge) and also de desktop version. I'll attach some pictures of the before and after running it on my computer and the notebook.
It is the order of evaluation. Your commands DiagonalizableMatrixQ[A] and Solve[Det[A - \[Lambda] IdentityMatrix[3]] == 0, \[Lambda]] were given BEFORE you gave a value to A. You should follow the order of the cells.
DiagonalizableMatrixQ[A]
Solve[Det[A - \[Lambda] IdentityMatrix[3]] == 0, \[Lambda]]
A
That solved it, thank you so much, I'm completely new to the Mathematica world, I really appreciate the support. Sorry if it was a dumb question.
