\(A = \frac{A}{2} + \frac{A}{2} \Rightarrow A = \frac{A}{2} + \frac{A}{2} + \frac{A'}{2} - \frac{A'}{2} \Rightarrow \frac{A+A'}{2} + \frac{A-A'}{2}\), onde \(\frac{A+A'}{2}\) é simérica, pois \((\frac{A+A'}{2})' = \frac{A'+A}{2}\); e \(\frac{A-A'}{2}\) é anti-simérica, pois \((\frac{A-A'}{2})' = \frac{A'-A}{2} = -(\frac{A-A'}{2})\).