Metamath Proof Explorer


Theorem readvrec

Description: For real numbers, the antiderivative of 1/x is ln|x|. (Contributed by SN, 30-Sep-2025)

Ref Expression
Hypothesis redvabs.d D = 0
Assertion readvrec dx D log x d x = x D 1 x

Proof

Step Hyp Ref Expression
1 redvabs.d D = 0
2 reelprrecn
3 2 a1i
4 cnelprrecn
5 4 a1i
6 dfrp2 + = 0 +∞
7 mnfxr −∞ *
8 7 a1i −∞ *
9 0xr 0 *
10 9 a1i 0 *
11 pnfxr +∞ *
12 11 a1i +∞ *
13 8 10 12 iocioodisjd −∞ 0 0 +∞ =
14 13 mptru −∞ 0 0 +∞ =
15 14 ineqcomi 0 +∞ −∞ 0 =
16 disjdif2 0 +∞ −∞ 0 = 0 +∞ −∞ 0 = 0 +∞
17 15 16 ax-mp 0 +∞ −∞ 0 = 0 +∞
18 6 17 eqtr4i + = 0 +∞ −∞ 0
19 ioosscn 0 +∞
20 ssdif 0 +∞ 0 +∞ −∞ 0 −∞ 0
21 19 20 ax-mp 0 +∞ −∞ 0 −∞ 0
22 18 21 eqsstri + −∞ 0
23 1 eleq2i x D x 0
24 eldifsn x 0 x x 0
25 23 24 bitri x D x x 0
26 25 simplbi x D x
27 26 recnd x D x
28 27 adantl x D x
29 25 simprbi x D x 0
30 29 adantl x D x 0
31 28 30 absrpcld x D x +
32 22 31 sselid x D x −∞ 0
33 negex 1 V
34 1ex 1 V
35 33 34 ifex if x < 0 1 1 V
36 35 a1i x D if x < 0 1 1 V
37 eldifi y −∞ 0 y
38 37 adantl y −∞ 0 y
39 eldifn y −∞ 0 ¬ y −∞ 0
40 mnflt0 −∞ < 0
41 ubioc1 −∞ * 0 * −∞ < 0 0 −∞ 0
42 7 9 40 41 mp3an 0 −∞ 0
43 eleq1 y = 0 y −∞ 0 0 −∞ 0
44 42 43 mpbiri y = 0 y −∞ 0
45 44 necon3bi ¬ y −∞ 0 y 0
46 39 45 syl y −∞ 0 y 0
47 46 adantl y −∞ 0 y 0
48 38 47 logcld y −∞ 0 log y
49 ovexd y −∞ 0 1 y V
50 1 redvmptabs dx D x d x = x D if x < 0 1 1
51 50 a1i dx D x d x = x D if x < 0 1 1
52 logf1o log : 0 1-1 onto ran log
53 f1of log : 0 1-1 onto ran log log : 0 ran log
54 52 53 ax-mp log : 0 ran log
55 54 a1i log : 0 ran log
56 55 feqmptd log = y 0 log y
57 56 mptru log = y 0 log y
58 57 reseq1i log −∞ 0 = y 0 log y −∞ 0
59 c0ex 0 V
60 59 snss 0 −∞ 0 0 −∞ 0
61 42 60 mpbi 0 −∞ 0
62 sscon 0 −∞ 0 −∞ 0 0
63 resmpt −∞ 0 0 y 0 log y −∞ 0 = y −∞ 0 log y
64 61 62 63 mp2b y 0 log y −∞ 0 = y −∞ 0 log y
65 58 64 eqtr2i y −∞ 0 log y = log −∞ 0
66 65 oveq2i dy −∞ 0 log y d y = D log −∞ 0
67 eqid −∞ 0 = −∞ 0
68 67 dvlog D log −∞ 0 = y −∞ 0 1 y
69 66 68 eqtri dy −∞ 0 log y d y = y −∞ 0 1 y
70 69 a1i dy −∞ 0 log y d y = y −∞ 0 1 y
71 fveq2 y = x log y = log x
72 oveq2 y = x 1 y = 1 x
73 3 5 32 36 48 49 51 70 71 72 dvmptco dx D log x d x = x D 1 x if x < 0 1 1
74 73 mptru dx D log x d x = x D 1 x if x < 0 1 1
75 ovif2 1 x if x < 0 1 1 = if x < 0 1 x -1 1 x 1
76 simpll x x 0 x < 0 x
77 76 recnd x x 0 x < 0 x
78 77 abscld x x 0 x < 0 x
79 78 recnd x x 0 x < 0 x
80 simplr x x 0 x < 0 x 0
81 77 80 absne0d x x 0 x < 0 x 0
82 79 81 reccld x x 0 x < 0 1 x
83 neg1cn 1
84 83 a1i x x 0 x < 0 1
85 82 84 mulcomd x x 0 x < 0 1 x -1 = -1 1 x
86 82 mulm1d x x 0 x < 0 -1 1 x = 1 x
87 1cnd x x 0 x < 0 1
88 87 79 81 divneg2d x x 0 x < 0 1 x = 1 x
89 0red x x 0 x < 0 0
90 simpr x x 0 x < 0 x < 0
91 76 89 90 ltled x x 0 x < 0 x 0
92 76 91 absnidd x x 0 x < 0 x = x
93 92 eqcomd x x 0 x < 0 x = x
94 77 93 negcon1ad x x 0 x < 0 x = x
95 94 oveq2d x x 0 x < 0 1 x = 1 x
96 88 95 eqtrd x x 0 x < 0 1 x = 1 x
97 85 86 96 3eqtrd x x 0 x < 0 1 x -1 = 1 x
98 25 97 sylanb x D x < 0 1 x -1 = 1 x
99 recn x x
100 99 abscld x x
101 100 ad2antrr x x 0 ¬ x < 0 x
102 99 ad2antrr x x 0 ¬ x < 0 x
103 simplr x x 0 ¬ x < 0 x 0
104 102 103 absne0d x x 0 ¬ x < 0 x 0
105 101 104 rereccld x x 0 ¬ x < 0 1 x
106 105 recnd x x 0 ¬ x < 0 1 x
107 106 mulridd x x 0 ¬ x < 0 1 x 1 = 1 x
108 simpll x x 0 ¬ x < 0 x
109 0red x x 0 0
110 simpl x x 0 x
111 109 110 lenltd x x 0 0 x ¬ x < 0
112 111 biimpar x x 0 ¬ x < 0 0 x
113 108 112 absidd x x 0 ¬ x < 0 x = x
114 113 oveq2d x x 0 ¬ x < 0 1 x = 1 x
115 107 114 eqtrd x x 0 ¬ x < 0 1 x 1 = 1 x
116 25 115 sylanb x D ¬ x < 0 1 x 1 = 1 x
117 98 116 ifeqda x D if x < 0 1 x -1 1 x 1 = 1 x
118 75 117 eqtrid x D 1 x if x < 0 1 1 = 1 x
119 118 mpteq2ia x D 1 x if x < 0 1 1 = x D 1 x
120 74 119 eqtri dx D log x d x = x D 1 x