Metamath Proof Explorer


Theorem addcjd

Description: A number plus its conjugate is twice its real part. Compare Proposition 10-3.4(h) of Gleason p. 133. (Contributed by Mario Carneiro, 29-May-2016)

Ref Expression
Hypothesis recld.1 φA
Assertion addcjd φA+A=2A

Proof

Step Hyp Ref Expression
1 recld.1 φA
2 addcj AA+A=2A
3 1 2 syl φA+A=2A