Metamath Proof Explorer


Theorem cjmulvali

Description: A complex number times its conjugate. (Contributed by NM, 2-Oct-1999)

Ref Expression
Hypothesis recl.1 A
Assertion cjmulvali A A = A 2 + A 2

Proof

Step Hyp Ref Expression
1 recl.1 A
2 cjmulval A A A = A 2 + A 2
3 1 2 ax-mp A A = A 2 + A 2