Theorem sq2

Description: The square of 2 is 4. (Contributed by NM, 22-Aug-1999)

	Ref	Expression
Assertion	sq2	⊢ ( 2 ↑ 2 ) = 4

Proof

Step	Hyp	Ref	Expression
1		2cn	⊢ 2 ∈ ℂ
2	1	sqvali	⊢ ( 2 ↑ 2 ) = ( 2 · 2 )
3		2t2e4	⊢ ( 2 · 2 ) = 4
4	2 3	eqtri	⊢ ( 2 ↑ 2 ) = 4