Theorem 2cnALT

Description: Alternate proof of 2cn . Shorter but uses more axioms. Similar proofs are possible for 3cn , ... , 9cn . (Contributed by NM, 30-Jul-2004) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Assertion	2cnALT	⊢ 2 ∈ ℂ

Proof

Step	Hyp	Ref	Expression
1		2re	⊢ 2 ∈ ℝ
2	1	recni	⊢ 2 ∈ ℂ