Would be grateful if anyone could help on this.
Let Matrix A = 1 2 1
2 4 2
1 2 1
Find orthogonal matrix P such that (P-1)AP is diagonal, where P-1 is P inverse?
Thanks
Read this: http://www.fen.bilkent.edu.tr/~degt/math220/diag.pdf
And this: Diagonalization
And this: Diagonalization
Now .... are you still stuck?