lognegb - Metamath Proof Explorer

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Theorem lognegb 26497

Description: If a number has imaginary part equal to π, then it is on the negative real axis and vice-versa. (Contributed by Mario Carneiro, 23-Sep-2014.)

**Assertion**
Ref	Expression
lognegb	⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (-𝐴 ∈ ℝ⁺ ↔ (ℑ‘(log‘𝐴)) = π))

**Proof of Theorem lognegb**
Step	Hyp	Ref	Expression
1		logneg 26495	. . . . 5 ⊢ (-𝐴 ∈ ℝ⁺ → (log‘--𝐴) = ((log‘-𝐴) + (i · π)))
2	1	fveq2d 6826	. . . 4 ⊢ (-𝐴 ∈ ℝ⁺ → (ℑ‘(log‘--𝐴)) = (ℑ‘((log‘-𝐴) + (i · π))))
3		relogcl 26482	. . . . 5 ⊢ (-𝐴 ∈ ℝ⁺ → (log‘-𝐴) ∈ ℝ)
4		pire 26364	. . . . 5 ⊢ π ∈ ℝ
5		crim 15022	. . . . 5 ⊢ (((log‘-𝐴) ∈ ℝ ∧ π ∈ ℝ) → (ℑ‘((log‘-𝐴) + (i · π))) = π)
6	3, 4, 5	sylancl 586	. . . 4 ⊢ (-𝐴 ∈ ℝ⁺ → (ℑ‘((log‘-𝐴) + (i · π))) = π)
7	2, 6	eqtrd 2764	. . 3 ⊢ (-𝐴 ∈ ℝ⁺ → (ℑ‘(log‘--𝐴)) = π)
8		negneg 11414	. . . . . 6 ⊢ (𝐴 ∈ ℂ → --𝐴 = 𝐴)
9	8	adantr 480	. . . . 5 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → --𝐴 = 𝐴)
10	9	fveq2d 6826	. . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (log‘--𝐴) = (log‘𝐴))
11	10	fveqeq2d 6830	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → ((ℑ‘(log‘--𝐴)) = π ↔ (ℑ‘(log‘𝐴)) = π))
12	7, 11	imbitrid 244	. 2 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (-𝐴 ∈ ℝ⁺ → (ℑ‘(log‘𝐴)) = π))
13		logcl 26475	. . . . . . 7 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (log‘𝐴) ∈ ℂ)
14	13	replimd 15104	. . . . . 6 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (log‘𝐴) = ((ℜ‘(log‘𝐴)) + (i · (ℑ‘(log‘𝐴)))))
15	14	fveq2d 6826	. . . . 5 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (exp‘(log‘𝐴)) = (exp‘((ℜ‘(log‘𝐴)) + (i · (ℑ‘(log‘𝐴))))))
16		eflog 26483	. . . . 5 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (exp‘(log‘𝐴)) = 𝐴)
17	13	recld 15101	. . . . . . 7 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (ℜ‘(log‘𝐴)) ∈ ℝ)
18	17	recnd 11143	. . . . . 6 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (ℜ‘(log‘𝐴)) ∈ ℂ)
19		ax-icn 11068	. . . . . . 7 ⊢ i ∈ ℂ
20	13	imcld 15102	. . . . . . . 8 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (ℑ‘(log‘𝐴)) ∈ ℝ)
21	20	recnd 11143	. . . . . . 7 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (ℑ‘(log‘𝐴)) ∈ ℂ)
22		mulcl 11093	. . . . . . 7 ⊢ ((i ∈ ℂ ∧ (ℑ‘(log‘𝐴)) ∈ ℂ) → (i · (ℑ‘(log‘𝐴))) ∈ ℂ)
23	19, 21, 22	sylancr 587	. . . . . 6 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (i · (ℑ‘(log‘𝐴))) ∈ ℂ)
24		efadd 16001	. . . . . 6 ⊢ (((ℜ‘(log‘𝐴)) ∈ ℂ ∧ (i · (ℑ‘(log‘𝐴))) ∈ ℂ) → (exp‘((ℜ‘(log‘𝐴)) + (i · (ℑ‘(log‘𝐴))))) = ((exp‘(ℜ‘(log‘𝐴))) · (exp‘(i · (ℑ‘(log‘𝐴))))))
25	18, 23, 24	syl2anc 584	. . . . 5 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (exp‘((ℜ‘(log‘𝐴)) + (i · (ℑ‘(log‘𝐴))))) = ((exp‘(ℜ‘(log‘𝐴))) · (exp‘(i · (ℑ‘(log‘𝐴))))))
26	15, 16, 25	3eqtr3d 2772	. . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → 𝐴 = ((exp‘(ℜ‘(log‘𝐴))) · (exp‘(i · (ℑ‘(log‘𝐴))))))
27		oveq2 7357	. . . . . . . 8 ⊢ ((ℑ‘(log‘𝐴)) = π → (i · (ℑ‘(log‘𝐴))) = (i · π))
28	27	fveq2d 6826	. . . . . . 7 ⊢ ((ℑ‘(log‘𝐴)) = π → (exp‘(i · (ℑ‘(log‘𝐴)))) = (exp‘(i · π)))
29		efipi 26380	. . . . . . 7 ⊢ (exp‘(i · π)) = -1
30	28, 29	eqtrdi 2780	. . . . . 6 ⊢ ((ℑ‘(log‘𝐴)) = π → (exp‘(i · (ℑ‘(log‘𝐴)))) = -1)
31	30	oveq2d 7365	. . . . 5 ⊢ ((ℑ‘(log‘𝐴)) = π → ((exp‘(ℜ‘(log‘𝐴))) · (exp‘(i · (ℑ‘(log‘𝐴))))) = ((exp‘(ℜ‘(log‘𝐴))) · -1))
32	31	eqeq2d 2740	. . . 4 ⊢ ((ℑ‘(log‘𝐴)) = π → (𝐴 = ((exp‘(ℜ‘(log‘𝐴))) · (exp‘(i · (ℑ‘(log‘𝐴))))) ↔ 𝐴 = ((exp‘(ℜ‘(log‘𝐴))) · -1)))
33	26, 32	syl5ibcom 245	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → ((ℑ‘(log‘𝐴)) = π → 𝐴 = ((exp‘(ℜ‘(log‘𝐴))) · -1)))
34	17	rpefcld 16014	. . . . . . . . . 10 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (exp‘(ℜ‘(log‘𝐴))) ∈ ℝ⁺)
35	34	rpcnd 12939	. . . . . . . . 9 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (exp‘(ℜ‘(log‘𝐴))) ∈ ℂ)
36		neg1cn 12113	. . . . . . . . 9 ⊢ -1 ∈ ℂ
37		mulcom 11095	. . . . . . . . 9 ⊢ (((exp‘(ℜ‘(log‘𝐴))) ∈ ℂ ∧ -1 ∈ ℂ) → ((exp‘(ℜ‘(log‘𝐴))) · -1) = (-1 · (exp‘(ℜ‘(log‘𝐴)))))
38	35, 36, 37	sylancl 586	. . . . . . . 8 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → ((exp‘(ℜ‘(log‘𝐴))) · -1) = (-1 · (exp‘(ℜ‘(log‘𝐴)))))
39	35	mulm1d 11572	. . . . . . . 8 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (-1 · (exp‘(ℜ‘(log‘𝐴)))) = -(exp‘(ℜ‘(log‘𝐴))))
40	38, 39	eqtrd 2764	. . . . . . 7 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → ((exp‘(ℜ‘(log‘𝐴))) · -1) = -(exp‘(ℜ‘(log‘𝐴))))
41	40	negeqd 11357	. . . . . 6 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → -((exp‘(ℜ‘(log‘𝐴))) · -1) = --(exp‘(ℜ‘(log‘𝐴))))
42	35	negnegd 11466	. . . . . 6 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → --(exp‘(ℜ‘(log‘𝐴))) = (exp‘(ℜ‘(log‘𝐴))))
43	41, 42	eqtrd 2764	. . . . 5 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → -((exp‘(ℜ‘(log‘𝐴))) · -1) = (exp‘(ℜ‘(log‘𝐴))))
44	43, 34	eqeltrd 2828	. . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → -((exp‘(ℜ‘(log‘𝐴))) · -1) ∈ ℝ⁺)
45		negeq 11355	. . . . 5 ⊢ (𝐴 = ((exp‘(ℜ‘(log‘𝐴))) · -1) → -𝐴 = -((exp‘(ℜ‘(log‘𝐴))) · -1))
46	45	eleq1d 2813	. . . 4 ⊢ (𝐴 = ((exp‘(ℜ‘(log‘𝐴))) · -1) → (-𝐴 ∈ ℝ⁺ ↔ -((exp‘(ℜ‘(log‘𝐴))) · -1) ∈ ℝ⁺))
47	44, 46	syl5ibrcom 247	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (𝐴 = ((exp‘(ℜ‘(log‘𝐴))) · -1) → -𝐴 ∈ ℝ⁺))
48	33, 47	syld 47	. 2 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → ((ℑ‘(log‘𝐴)) = π → -𝐴 ∈ ℝ⁺))
49	12, 48	impbid 212	1 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (-𝐴 ∈ ℝ⁺ ↔ (ℑ‘(log‘𝐴)) = π))

Colors of variables: wff setvar class

Syntax hints: → wi 4 ↔ wb 206 ∧ wa 395 = wceq 1540 ∈ wcel 2109 ≠ wne 2925 ‘cfv 6482 (class class class)co 7349 ℂcc 11007 ℝcr 11008 0cc0 11009 1c1 11010 ici 11011 + caddc 11012 · cmul 11014 -cneg 11348 ℝ⁺crp 12893 ℜcre 15004 ℑcim 15005 expce 15968 πcpi 15973 logclog 26461

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1795 ax-4 1809 ax-5 1910 ax-6 1967 ax-7 2008 ax-8 2111 ax-9 2119 ax-10 2142 ax-11 2158 ax-12 2178 ax-ext 2701 ax-rep 5218 ax-sep 5235 ax-nul 5245 ax-pow 5304 ax-pr 5371 ax-un 7671 ax-inf2 9537 ax-cnex 11065 ax-resscn 11066 ax-1cn 11067 ax-icn 11068 ax-addcl 11069 ax-addrcl 11070 ax-mulcl 11071 ax-mulrcl 11072 ax-mulcom 11073 ax-addass 11074 ax-mulass 11075 ax-distr 11076 ax-i2m1 11077 ax-1ne0 11078 ax-1rid 11079 ax-rnegex 11080 ax-rrecex 11081 ax-cnre 11082 ax-pre-lttri 11083 ax-pre-lttrn 11084 ax-pre-ltadd 11085 ax-pre-mulgt0 11086 ax-pre-sup 11087 ax-addf 11088

This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-3or 1087 df-3an 1088 df-tru 1543 df-fal 1553 df-ex 1780 df-nf 1784 df-sb 2066 df-mo 2533 df-eu 2562 df-clab 2708 df-cleq 2721 df-clel 2803 df-nfc 2878 df-ne 2926 df-nel 3030 df-ral 3045 df-rex 3054 df-rmo 3343 df-reu 3344 df-rab 3395 df-v 3438 df-sbc 3743 df-csb 3852 df-dif 3906 df-un 3908 df-in 3910 df-ss 3920 df-pss 3923 df-nul 4285 df-if 4477 df-pw 4553 df-sn 4578 df-pr 4580 df-tp 4582 df-op 4584 df-uni 4859 df-int 4897 df-iun 4943 df-iin 4944 df-br 5093 df-opab 5155 df-mpt 5174 df-tr 5200 df-id 5514 df-eprel 5519 df-po 5527 df-so 5528 df-fr 5572 df-se 5573 df-we 5574 df-xp 5625 df-rel 5626 df-cnv 5627 df-co 5628 df-dm 5629 df-rn 5630 df-res 5631 df-ima 5632 df-pred 6249 df-ord 6310 df-on 6311 df-lim 6312 df-suc 6313 df-iota 6438 df-fun 6484 df-fn 6485 df-f 6486 df-f1 6487 df-fo 6488 df-f1o 6489 df-fv 6490 df-isom 6491 df-riota 7306 df-ov 7352 df-oprab 7353 df-mpo 7354 df-of 7613 df-om 7800 df-1st 7924 df-2nd 7925 df-supp 8094 df-frecs 8214 df-wrecs 8245 df-recs 8294 df-rdg 8332 df-1o 8388 df-2o 8389 df-er 8625 df-map 8755 df-pm 8756 df-ixp 8825 df-en 8873 df-dom 8874 df-sdom 8875 df-fin 8876 df-fsupp 9252 df-fi 9301 df-sup 9332 df-inf 9333 df-oi 9402 df-card 9835 df-pnf 11151 df-mnf 11152 df-xr 11153 df-ltxr 11154 df-le 11155 df-sub 11349 df-neg 11350 df-div 11778 df-nn 12129 df-2 12191 df-3 12192 df-4 12193 df-5 12194 df-6 12195 df-7 12196 df-8 12197 df-9 12198 df-n0 12385 df-z 12472 df-dec 12592 df-uz 12736 df-q 12850 df-rp 12894 df-xneg 13014 df-xadd 13015 df-xmul 13016 df-ioo 13252 df-ioc 13253 df-ico 13254 df-icc 13255 df-fz 13411 df-fzo 13558 df-fl 13696 df-mod 13774 df-seq 13909 df-exp 13969 df-fac 14181 df-bc 14210 df-hash 14238 df-shft 14974 df-cj 15006 df-re 15007 df-im 15008 df-sqrt 15142 df-abs 15143 df-limsup 15378 df-clim 15395 df-rlim 15396 df-sum 15594 df-ef 15974 df-sin 15976 df-cos 15977 df-pi 15979 df-struct 17058 df-sets 17075 df-slot 17093 df-ndx 17105 df-base 17121 df-ress 17142 df-plusg 17174 df-mulr 17175 df-starv 17176 df-sca 17177 df-vsca 17178 df-ip 17179 df-tset 17180 df-ple 17181 df-ds 17183 df-unif 17184 df-hom 17185 df-cco 17186 df-rest 17326 df-topn 17327 df-0g 17345 df-gsum 17346 df-topgen 17347 df-pt 17348 df-prds 17351 df-xrs 17406 df-qtop 17411 df-imas 17412 df-xps 17414 df-mre 17488 df-mrc 17489 df-acs 17491 df-mgm 18514 df-sgrp 18593 df-mnd 18609 df-submnd 18658 df-mulg 18947 df-cntz 19196 df-cmn 19661 df-psmet 21253 df-xmet 21254 df-met 21255 df-bl 21256 df-mopn 21257 df-fbas 21258 df-fg 21259 df-cnfld 21262 df-top 22779 df-topon 22796 df-topsp 22818 df-bases 22831 df-cld 22904 df-ntr 22905 df-cls 22906 df-nei 22983 df-lp 23021 df-perf 23022 df-cn 23112 df-cnp 23113 df-haus 23200 df-tx 23447 df-hmeo 23640 df-fil 23731 df-fm 23823 df-flim 23824 df-flf 23825 df-xms 24206 df-ms 24207 df-tms 24208 df-cncf 24769 df-limc 25765 df-dv 25766 df-log 26463

This theorem is referenced by: logcj 26513 argimgt0 26519 dvloglem 26555 logf1o2 26557 logrec 26671 ang180lem2 26718 angpieqvdlem2 26737 asinneg 26794 arginv 32700

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