Metamath Proof Explorer


Theorem logdivsum

Description: Asymptotic analysis of sum_ n <_ x , log n / n = ( log x ) ^ 2 / 2 + L + O ( log x / x ) . (Contributed by Mario Carneiro, 18-May-2016)

Ref Expression
Hypothesis logdivsum.1 𝐹 = ( 𝑦 ∈ ℝ+ ↦ ( Σ 𝑖 ∈ ( 1 ... ( ⌊ ‘ 𝑦 ) ) ( ( log ‘ 𝑖 ) / 𝑖 ) − ( ( ( log ‘ 𝑦 ) ↑ 2 ) / 2 ) ) )
Assertion logdivsum ( 𝐹 : ℝ+ ⟶ ℝ ∧ 𝐹 ∈ dom ⇝𝑟 ∧ ( ( 𝐹𝑟 𝐿𝐴 ∈ ℝ+ ∧ e ≤ 𝐴 ) → ( abs ‘ ( ( 𝐹𝐴 ) − 𝐿 ) ) ≤ ( ( log ‘ 𝐴 ) / 𝐴 ) ) )

Proof

Step Hyp Ref Expression
1 logdivsum.1 𝐹 = ( 𝑦 ∈ ℝ+ ↦ ( Σ 𝑖 ∈ ( 1 ... ( ⌊ ‘ 𝑦 ) ) ( ( log ‘ 𝑖 ) / 𝑖 ) − ( ( ( log ‘ 𝑦 ) ↑ 2 ) / 2 ) ) )
2 ioorp ( 0 (,) +∞ ) = ℝ+
3 2 eqcomi + = ( 0 (,) +∞ )
4 nnuz ℕ = ( ℤ ‘ 1 )
5 1zzd ( ⊤ → 1 ∈ ℤ )
6 ere e ∈ ℝ
7 6 a1i ( ⊤ → e ∈ ℝ )
8 0re 0 ∈ ℝ
9 epos 0 < e
10 8 6 9 ltleii 0 ≤ e
11 10 a1i ( ⊤ → 0 ≤ e )
12 1re 1 ∈ ℝ
13 addge02 ( ( 1 ∈ ℝ ∧ e ∈ ℝ ) → ( 0 ≤ e ↔ 1 ≤ ( e + 1 ) ) )
14 12 6 13 mp2an ( 0 ≤ e ↔ 1 ≤ ( e + 1 ) )
15 11 14 sylib ( ⊤ → 1 ≤ ( e + 1 ) )
16 8 a1i ( ⊤ → 0 ∈ ℝ )
17 relogcl ( 𝑦 ∈ ℝ+ → ( log ‘ 𝑦 ) ∈ ℝ )
18 17 adantl ( ( ⊤ ∧ 𝑦 ∈ ℝ+ ) → ( log ‘ 𝑦 ) ∈ ℝ )
19 18 resqcld ( ( ⊤ ∧ 𝑦 ∈ ℝ+ ) → ( ( log ‘ 𝑦 ) ↑ 2 ) ∈ ℝ )
20 19 rehalfcld ( ( ⊤ ∧ 𝑦 ∈ ℝ+ ) → ( ( ( log ‘ 𝑦 ) ↑ 2 ) / 2 ) ∈ ℝ )
21 rerpdivcl ( ( ( log ‘ 𝑦 ) ∈ ℝ ∧ 𝑦 ∈ ℝ+ ) → ( ( log ‘ 𝑦 ) / 𝑦 ) ∈ ℝ )
22 17 21 mpancom ( 𝑦 ∈ ℝ+ → ( ( log ‘ 𝑦 ) / 𝑦 ) ∈ ℝ )
23 22 adantl ( ( ⊤ ∧ 𝑦 ∈ ℝ+ ) → ( ( log ‘ 𝑦 ) / 𝑦 ) ∈ ℝ )
24 nnrp ( 𝑦 ∈ ℕ → 𝑦 ∈ ℝ+ )
25 24 23 sylan2 ( ( ⊤ ∧ 𝑦 ∈ ℕ ) → ( ( log ‘ 𝑦 ) / 𝑦 ) ∈ ℝ )
26 reelprrecn ℝ ∈ { ℝ , ℂ }
27 26 a1i ( ⊤ → ℝ ∈ { ℝ , ℂ } )
28 cnelprrecn ℂ ∈ { ℝ , ℂ }
29 28 a1i ( ⊤ → ℂ ∈ { ℝ , ℂ } )
30 18 recnd ( ( ⊤ ∧ 𝑦 ∈ ℝ+ ) → ( log ‘ 𝑦 ) ∈ ℂ )
31 ovexd ( ( ⊤ ∧ 𝑦 ∈ ℝ+ ) → ( 1 / 𝑦 ) ∈ V )
32 sqcl ( 𝑥 ∈ ℂ → ( 𝑥 ↑ 2 ) ∈ ℂ )
33 32 adantl ( ( ⊤ ∧ 𝑥 ∈ ℂ ) → ( 𝑥 ↑ 2 ) ∈ ℂ )
34 33 halfcld ( ( ⊤ ∧ 𝑥 ∈ ℂ ) → ( ( 𝑥 ↑ 2 ) / 2 ) ∈ ℂ )
35 simpr ( ( ⊤ ∧ 𝑥 ∈ ℂ ) → 𝑥 ∈ ℂ )
36 relogf1o ( log ↾ ℝ+ ) : ℝ+1-1-onto→ ℝ
37 f1of ( ( log ↾ ℝ+ ) : ℝ+1-1-onto→ ℝ → ( log ↾ ℝ+ ) : ℝ+ ⟶ ℝ )
38 36 37 mp1i ( ⊤ → ( log ↾ ℝ+ ) : ℝ+ ⟶ ℝ )
39 38 feqmptd ( ⊤ → ( log ↾ ℝ+ ) = ( 𝑦 ∈ ℝ+ ↦ ( ( log ↾ ℝ+ ) ‘ 𝑦 ) ) )
40 fvres ( 𝑦 ∈ ℝ+ → ( ( log ↾ ℝ+ ) ‘ 𝑦 ) = ( log ‘ 𝑦 ) )
41 40 mpteq2ia ( 𝑦 ∈ ℝ+ ↦ ( ( log ↾ ℝ+ ) ‘ 𝑦 ) ) = ( 𝑦 ∈ ℝ+ ↦ ( log ‘ 𝑦 ) )
42 39 41 eqtrdi ( ⊤ → ( log ↾ ℝ+ ) = ( 𝑦 ∈ ℝ+ ↦ ( log ‘ 𝑦 ) ) )
43 42 oveq2d ( ⊤ → ( ℝ D ( log ↾ ℝ+ ) ) = ( ℝ D ( 𝑦 ∈ ℝ+ ↦ ( log ‘ 𝑦 ) ) ) )
44 dvrelog ( ℝ D ( log ↾ ℝ+ ) ) = ( 𝑦 ∈ ℝ+ ↦ ( 1 / 𝑦 ) )
45 43 44 eqtr3di ( ⊤ → ( ℝ D ( 𝑦 ∈ ℝ+ ↦ ( log ‘ 𝑦 ) ) ) = ( 𝑦 ∈ ℝ+ ↦ ( 1 / 𝑦 ) ) )
46 ovexd ( ( ⊤ ∧ 𝑥 ∈ ℂ ) → ( 2 · 𝑥 ) ∈ V )
47 2nn 2 ∈ ℕ
48 dvexp ( 2 ∈ ℕ → ( ℂ D ( 𝑥 ∈ ℂ ↦ ( 𝑥 ↑ 2 ) ) ) = ( 𝑥 ∈ ℂ ↦ ( 2 · ( 𝑥 ↑ ( 2 − 1 ) ) ) ) )
49 47 48 mp1i ( ⊤ → ( ℂ D ( 𝑥 ∈ ℂ ↦ ( 𝑥 ↑ 2 ) ) ) = ( 𝑥 ∈ ℂ ↦ ( 2 · ( 𝑥 ↑ ( 2 − 1 ) ) ) ) )
50 2m1e1 ( 2 − 1 ) = 1
51 50 oveq2i ( 𝑥 ↑ ( 2 − 1 ) ) = ( 𝑥 ↑ 1 )
52 exp1 ( 𝑥 ∈ ℂ → ( 𝑥 ↑ 1 ) = 𝑥 )
53 52 adantl ( ( ⊤ ∧ 𝑥 ∈ ℂ ) → ( 𝑥 ↑ 1 ) = 𝑥 )
54 51 53 eqtrid ( ( ⊤ ∧ 𝑥 ∈ ℂ ) → ( 𝑥 ↑ ( 2 − 1 ) ) = 𝑥 )
55 54 oveq2d ( ( ⊤ ∧ 𝑥 ∈ ℂ ) → ( 2 · ( 𝑥 ↑ ( 2 − 1 ) ) ) = ( 2 · 𝑥 ) )
56 55 mpteq2dva ( ⊤ → ( 𝑥 ∈ ℂ ↦ ( 2 · ( 𝑥 ↑ ( 2 − 1 ) ) ) ) = ( 𝑥 ∈ ℂ ↦ ( 2 · 𝑥 ) ) )
57 49 56 eqtrd ( ⊤ → ( ℂ D ( 𝑥 ∈ ℂ ↦ ( 𝑥 ↑ 2 ) ) ) = ( 𝑥 ∈ ℂ ↦ ( 2 · 𝑥 ) ) )
58 2cnd ( ⊤ → 2 ∈ ℂ )
59 2ne0 2 ≠ 0
60 59 a1i ( ⊤ → 2 ≠ 0 )
61 29 33 46 57 58 60 dvmptdivc ( ⊤ → ( ℂ D ( 𝑥 ∈ ℂ ↦ ( ( 𝑥 ↑ 2 ) / 2 ) ) ) = ( 𝑥 ∈ ℂ ↦ ( ( 2 · 𝑥 ) / 2 ) ) )
62 2cn 2 ∈ ℂ
63 divcan3 ( ( 𝑥 ∈ ℂ ∧ 2 ∈ ℂ ∧ 2 ≠ 0 ) → ( ( 2 · 𝑥 ) / 2 ) = 𝑥 )
64 62 59 63 mp3an23 ( 𝑥 ∈ ℂ → ( ( 2 · 𝑥 ) / 2 ) = 𝑥 )
65 64 adantl ( ( ⊤ ∧ 𝑥 ∈ ℂ ) → ( ( 2 · 𝑥 ) / 2 ) = 𝑥 )
66 65 mpteq2dva ( ⊤ → ( 𝑥 ∈ ℂ ↦ ( ( 2 · 𝑥 ) / 2 ) ) = ( 𝑥 ∈ ℂ ↦ 𝑥 ) )
67 61 66 eqtrd ( ⊤ → ( ℂ D ( 𝑥 ∈ ℂ ↦ ( ( 𝑥 ↑ 2 ) / 2 ) ) ) = ( 𝑥 ∈ ℂ ↦ 𝑥 ) )
68 oveq1 ( 𝑥 = ( log ‘ 𝑦 ) → ( 𝑥 ↑ 2 ) = ( ( log ‘ 𝑦 ) ↑ 2 ) )
69 68 oveq1d ( 𝑥 = ( log ‘ 𝑦 ) → ( ( 𝑥 ↑ 2 ) / 2 ) = ( ( ( log ‘ 𝑦 ) ↑ 2 ) / 2 ) )
70 id ( 𝑥 = ( log ‘ 𝑦 ) → 𝑥 = ( log ‘ 𝑦 ) )
71 27 29 30 31 34 35 45 67 69 70 dvmptco ( ⊤ → ( ℝ D ( 𝑦 ∈ ℝ+ ↦ ( ( ( log ‘ 𝑦 ) ↑ 2 ) / 2 ) ) ) = ( 𝑦 ∈ ℝ+ ↦ ( ( log ‘ 𝑦 ) · ( 1 / 𝑦 ) ) ) )
72 rpcn ( 𝑦 ∈ ℝ+𝑦 ∈ ℂ )
73 72 adantl ( ( ⊤ ∧ 𝑦 ∈ ℝ+ ) → 𝑦 ∈ ℂ )
74 rpne0 ( 𝑦 ∈ ℝ+𝑦 ≠ 0 )
75 74 adantl ( ( ⊤ ∧ 𝑦 ∈ ℝ+ ) → 𝑦 ≠ 0 )
76 30 73 75 divrecd ( ( ⊤ ∧ 𝑦 ∈ ℝ+ ) → ( ( log ‘ 𝑦 ) / 𝑦 ) = ( ( log ‘ 𝑦 ) · ( 1 / 𝑦 ) ) )
77 76 mpteq2dva ( ⊤ → ( 𝑦 ∈ ℝ+ ↦ ( ( log ‘ 𝑦 ) / 𝑦 ) ) = ( 𝑦 ∈ ℝ+ ↦ ( ( log ‘ 𝑦 ) · ( 1 / 𝑦 ) ) ) )
78 71 77 eqtr4d ( ⊤ → ( ℝ D ( 𝑦 ∈ ℝ+ ↦ ( ( ( log ‘ 𝑦 ) ↑ 2 ) / 2 ) ) ) = ( 𝑦 ∈ ℝ+ ↦ ( ( log ‘ 𝑦 ) / 𝑦 ) ) )
79 fveq2 ( 𝑦 = 𝑖 → ( log ‘ 𝑦 ) = ( log ‘ 𝑖 ) )
80 id ( 𝑦 = 𝑖𝑦 = 𝑖 )
81 79 80 oveq12d ( 𝑦 = 𝑖 → ( ( log ‘ 𝑦 ) / 𝑦 ) = ( ( log ‘ 𝑖 ) / 𝑖 ) )
82 simp3r ( ( ⊤ ∧ ( 𝑦 ∈ ℝ+𝑖 ∈ ℝ+ ) ∧ ( e ≤ 𝑦𝑦𝑖 ) ) → 𝑦𝑖 )
83 simp2l ( ( ⊤ ∧ ( 𝑦 ∈ ℝ+𝑖 ∈ ℝ+ ) ∧ ( e ≤ 𝑦𝑦𝑖 ) ) → 𝑦 ∈ ℝ+ )
84 83 rpred ( ( ⊤ ∧ ( 𝑦 ∈ ℝ+𝑖 ∈ ℝ+ ) ∧ ( e ≤ 𝑦𝑦𝑖 ) ) → 𝑦 ∈ ℝ )
85 simp3l ( ( ⊤ ∧ ( 𝑦 ∈ ℝ+𝑖 ∈ ℝ+ ) ∧ ( e ≤ 𝑦𝑦𝑖 ) ) → e ≤ 𝑦 )
86 simp2r ( ( ⊤ ∧ ( 𝑦 ∈ ℝ+𝑖 ∈ ℝ+ ) ∧ ( e ≤ 𝑦𝑦𝑖 ) ) → 𝑖 ∈ ℝ+ )
87 86 rpred ( ( ⊤ ∧ ( 𝑦 ∈ ℝ+𝑖 ∈ ℝ+ ) ∧ ( e ≤ 𝑦𝑦𝑖 ) ) → 𝑖 ∈ ℝ )
88 6 a1i ( ( ⊤ ∧ ( 𝑦 ∈ ℝ+𝑖 ∈ ℝ+ ) ∧ ( e ≤ 𝑦𝑦𝑖 ) ) → e ∈ ℝ )
89 88 84 87 85 82 letrd ( ( ⊤ ∧ ( 𝑦 ∈ ℝ+𝑖 ∈ ℝ+ ) ∧ ( e ≤ 𝑦𝑦𝑖 ) ) → e ≤ 𝑖 )
90 logdivle ( ( ( 𝑦 ∈ ℝ ∧ e ≤ 𝑦 ) ∧ ( 𝑖 ∈ ℝ ∧ e ≤ 𝑖 ) ) → ( 𝑦𝑖 ↔ ( ( log ‘ 𝑖 ) / 𝑖 ) ≤ ( ( log ‘ 𝑦 ) / 𝑦 ) ) )
91 84 85 87 89 90 syl22anc ( ( ⊤ ∧ ( 𝑦 ∈ ℝ+𝑖 ∈ ℝ+ ) ∧ ( e ≤ 𝑦𝑦𝑖 ) ) → ( 𝑦𝑖 ↔ ( ( log ‘ 𝑖 ) / 𝑖 ) ≤ ( ( log ‘ 𝑦 ) / 𝑦 ) ) )
92 82 91 mpbid ( ( ⊤ ∧ ( 𝑦 ∈ ℝ+𝑖 ∈ ℝ+ ) ∧ ( e ≤ 𝑦𝑦𝑖 ) ) → ( ( log ‘ 𝑖 ) / 𝑖 ) ≤ ( ( log ‘ 𝑦 ) / 𝑦 ) )
93 72 cxp1d ( 𝑦 ∈ ℝ+ → ( 𝑦𝑐 1 ) = 𝑦 )
94 93 oveq2d ( 𝑦 ∈ ℝ+ → ( ( log ‘ 𝑦 ) / ( 𝑦𝑐 1 ) ) = ( ( log ‘ 𝑦 ) / 𝑦 ) )
95 94 mpteq2ia ( 𝑦 ∈ ℝ+ ↦ ( ( log ‘ 𝑦 ) / ( 𝑦𝑐 1 ) ) ) = ( 𝑦 ∈ ℝ+ ↦ ( ( log ‘ 𝑦 ) / 𝑦 ) )
96 1rp 1 ∈ ℝ+
97 cxploglim ( 1 ∈ ℝ+ → ( 𝑦 ∈ ℝ+ ↦ ( ( log ‘ 𝑦 ) / ( 𝑦𝑐 1 ) ) ) ⇝𝑟 0 )
98 96 97 mp1i ( ⊤ → ( 𝑦 ∈ ℝ+ ↦ ( ( log ‘ 𝑦 ) / ( 𝑦𝑐 1 ) ) ) ⇝𝑟 0 )
99 95 98 eqbrtrrid ( ⊤ → ( 𝑦 ∈ ℝ+ ↦ ( ( log ‘ 𝑦 ) / 𝑦 ) ) ⇝𝑟 0 )
100 fveq2 ( 𝑦 = 𝐴 → ( log ‘ 𝑦 ) = ( log ‘ 𝐴 ) )
101 id ( 𝑦 = 𝐴𝑦 = 𝐴 )
102 100 101 oveq12d ( 𝑦 = 𝐴 → ( ( log ‘ 𝑦 ) / 𝑦 ) = ( ( log ‘ 𝐴 ) / 𝐴 ) )
103 3 4 5 7 15 16 20 23 25 78 81 92 1 99 102 dvfsumrlim3 ( ⊤ → ( 𝐹 : ℝ+ ⟶ ℝ ∧ 𝐹 ∈ dom ⇝𝑟 ∧ ( ( 𝐹𝑟 𝐿𝐴 ∈ ℝ+ ∧ e ≤ 𝐴 ) → ( abs ‘ ( ( 𝐹𝐴 ) − 𝐿 ) ) ≤ ( ( log ‘ 𝐴 ) / 𝐴 ) ) ) )
104 103 mptru ( 𝐹 : ℝ+ ⟶ ℝ ∧ 𝐹 ∈ dom ⇝𝑟 ∧ ( ( 𝐹𝑟 𝐿𝐴 ∈ ℝ+ ∧ e ≤ 𝐴 ) → ( abs ‘ ( ( 𝐹𝐴 ) − 𝐿 ) ) ≤ ( ( log ‘ 𝐴 ) / 𝐴 ) ) )