Definition df-e 12200

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 12194	. 2 class _e
2		c1 8023	. . 3 class 1
3		ce 12193	. . 3 class exp
4	2, 3	cfv 5324	. 2 class ( exp ` 1 )
5	1, 4	wceq 1395	1 wff _e = ( exp ` 1 )

This definition is referenced by:  esum  12213  ere  12221  ege2le3  12222  efzval  12234  reeff1oleme  15486  loge  15581  logdivlti  15595