Metamath Proof Explorer


Theorem logfacrlim2

Description: Write out logfacrlim as a sum of logs. (Contributed by Mario Carneiro, 18-May-2016) (Revised by Mario Carneiro, 22-May-2016)

Ref Expression
Assertion logfacrlim2 ⊢ x ∈ ℝ + ⟼ ∑ n = 1 x log ⁡ x n x ⇝ℝ 1

Proof

Step Hyp Ref Expression
1 1nn0 ⊢ 1 ∈ ℕ 0
2 logexprlim ⊢ 1 ∈ ℕ 0 → x ∈ ℝ + ⟼ ∑ n = 1 x log ⁡ x n 1 x ⇝ℝ 1 !
3 1 2 ax-mp ⊢ x ∈ ℝ + ⟼ ∑ n = 1 x log ⁡ x n 1 x ⇝ℝ 1 !
4 elfznn ⊢ n ∈ 1 … x → n ∈ ℕ
5 4 nnrpd ⊢ n ∈ 1 … x → n ∈ ℝ +
6 rpdivcl ⊢ x ∈ ℝ + ∧ n ∈ ℝ + → x n ∈ ℝ +
7 5 6 sylan2 ⊢ x ∈ ℝ + ∧ n ∈ 1 … x → x n ∈ ℝ +
8 7 relogcld ⊢ x ∈ ℝ + ∧ n ∈ 1 … x → log ⁡ x n ∈ ℝ
9 8 recnd ⊢ x ∈ ℝ + ∧ n ∈ 1 … x → log ⁡ x n ∈ ℂ
10 9 exp1d ⊢ x ∈ ℝ + ∧ n ∈ 1 … x → log ⁡ x n 1 = log ⁡ x n
11 10 sumeq2dv ⊢ x ∈ ℝ + → ∑ n = 1 x log ⁡ x n 1 = ∑ n = 1 x log ⁡ x n
12 11 oveq1d ⊢ x ∈ ℝ + → ∑ n = 1 x log ⁡ x n 1 x = ∑ n = 1 x log ⁡ x n x
13 fzfid ⊢ x ∈ ℝ + → 1 … x ∈ Fin
14 rpcn ⊢ x ∈ ℝ + → x ∈ ℂ
15 rpne0 ⊢ x ∈ ℝ + → x ≠ 0
16 13 14 9 15 fsumdivc ⊢ x ∈ ℝ + → ∑ n = 1 x log ⁡ x n x = ∑ n = 1 x log ⁡ x n x
17 12 16 eqtrd ⊢ x ∈ ℝ + → ∑ n = 1 x log ⁡ x n 1 x = ∑ n = 1 x log ⁡ x n x
18 17 mpteq2ia ⊢ x ∈ ℝ + ⟼ ∑ n = 1 x log ⁡ x n 1 x = x ∈ ℝ + ⟼ ∑ n = 1 x log ⁡ x n x
19 fac1 ⊢ 1 ! = 1
20 3 18 19 3brtr3i ⊢ x ∈ ℝ + ⟼ ∑ n = 1 x log ⁡ x n x ⇝ℝ 1