How to prove this theorem? Let S be a real symmetric matrix. Then S has only real eigenvalues.?
1 Answer
Apr 5, 2018
See below:
Explanation:
Let
Consider the number (strictly speaking -
Here "+" denotes Hermitian adjoint - i,e, a transpose followed by a complex conjugation.
Taking the adjoint of both sides, we get
Using
or
Since
and so
Since