Metamath Proof Explorer


Theorem cjmulge0i

Description: A complex number times its conjugate is nonnegative. (Contributed by NM, 28-May-1999)

Ref Expression
Hypothesis recl.1 𝐴 ∈ ℂ
Assertion cjmulge0i 0 ≤ ( 𝐴 · ( ∗ ‘ 𝐴 ) )

Proof

Step Hyp Ref Expression
1 recl.1 𝐴 ∈ ℂ
2 cjmulge0 ( 𝐴 ∈ ℂ → 0 ≤ ( 𝐴 · ( ∗ ‘ 𝐴 ) ) )
3 1 2 ax-mp 0 ≤ ( 𝐴 · ( ∗ ‘ 𝐴 ) )