Definition df-e 12416

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 12410	. 2 class _e
2		c1 8180	. . 3 class 1
3		ce 12409	. . 3 class exp
4	2, 3	cfv 5377	. 2 class ( exp ` 1 )
5	1, 4	wceq 1402	1 wff _e = ( exp ` 1 )

This definition is used by:  esum  12429  ere  12437  ege2le3  12438  efzval  12450  reeff1oleme  15873  loge  15968  logdivlti  15982