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Definition df-ef 15411
Description: Define the exponential function. Its value at the complex number 𝐴 is (exp‘𝐴) and is called the "exponential of 𝐴"; see efval 15423. (Contributed by NM, 14-Mar-2005.)
Assertion
Ref Expression
df-ef exp = (𝑥 ∈ ℂ ↦ Σ𝑘 ∈ ℕ0 ((𝑥𝑘) / (!‘𝑘)))
Distinct variable group:   𝑥,𝑘

Detailed syntax breakdown of Definition df-ef
StepHypRef Expression
1 ce 15405 . 2 class exp
2 vx . . 3 setvar 𝑥
3 cc 10524 . . 3 class
4 cn0 11886 . . . 4 class 0
52cv 1527 . . . . . 6 class 𝑥
6 vk . . . . . . 7 setvar 𝑘
76cv 1527 . . . . . 6 class 𝑘
8 cexp 13419 . . . . . 6 class
95, 7, 8co 7145 . . . . 5 class (𝑥𝑘)
10 cfa 13623 . . . . . 6 class !
117, 10cfv 6349 . . . . 5 class (!‘𝑘)
12 cdiv 11286 . . . . 5 class /
139, 11, 12co 7145 . . . 4 class ((𝑥𝑘) / (!‘𝑘))
144, 13, 6csu 15032 . . 3 class Σ𝑘 ∈ ℕ0 ((𝑥𝑘) / (!‘𝑘))
152, 3, 14cmpt 5138 . 2 class (𝑥 ∈ ℂ ↦ Σ𝑘 ∈ ℕ0 ((𝑥𝑘) / (!‘𝑘)))
161, 15wceq 1528 1 wff exp = (𝑥 ∈ ℂ ↦ Σ𝑘 ∈ ℕ0 ((𝑥𝑘) / (!‘𝑘)))
Colors of variables: wff setvar class
This definition is referenced by:  efval  15423  eff  15425
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