Definition df-e 12394

Description: Define Euler's constant _e = 2.71828.... (Contributed by NM, 14-Mar-2005.)

Assertion

Ref	Expression
df-e	|- _e = ( exp ` 1 )

Detailed syntax breakdown of Definition df-e

Step	Hyp	Ref	Expression
1		ceu 12388	. 2 class _e
2		c1 8170	. . 3 class 1
3		ce 12387	. . 3 class exp
4	2, 3	cfv 5372	. 2 class ( exp ` 1 )
5	1, 4	wceq 1402	1 wff _e = ( exp ` 1 )

This definition is referenced by:  esum  12407  ere  12415  ege2le3  12416  efzval  12428  reeff1oleme  15796  loge  15891  logdivlti  15905