If A=a bb a and A2=α ββ α, then
α=a2+b2,β=2ab
α=a2+b2,β=a2−b2
α=2ab,β=a2+b2
α=a2+b2,β=−2ab
A2=a bb aa bb a=a2+b22ab2aba2+b2
∴ αββα=a2+b22ab2aba2+b2⇒ α=a2+b2,β=2ab