Metamath Proof Explorer

Definition df-e

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

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

Detailed syntax breakdown

Step Hyp Ref Expression
0 ceu 
 |-  _e
1 ce 
 |-  exp
2 c1 
 |-  1
3 2 1 cfv 
 |-  ( exp ` 1 )
4 0 3 wceq 
 |-  _e = ( exp ` 1 )