lognegb - Metamath Proof Explorer

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Theorem lognegb 25755

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 25753	. . . . 5 ⊢ (-𝐴 ∈ ℝ⁺ → (log‘--𝐴) = ((log‘-𝐴) + (i · π)))
2	1	fveq2d 6770	. . . 4 ⊢ (-𝐴 ∈ ℝ⁺ → (ℑ‘(log‘--𝐴)) = (ℑ‘((log‘-𝐴) + (i · π))))
3		relogcl 25741	. . . . 5 ⊢ (-𝐴 ∈ ℝ⁺ → (log‘-𝐴) ∈ ℝ)
4		pire 25625	. . . . 5 ⊢ π ∈ ℝ
5		crim 14836	. . . . 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 2778	. . 3 ⊢ (-𝐴 ∈ ℝ⁺ → (ℑ‘(log‘--𝐴)) = π)
8		negneg 11281	. . . . . 6 ⊢ (𝐴 ∈ ℂ → --𝐴 = 𝐴)
9	8	adantr 481	. . . . 5 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → --𝐴 = 𝐴)
10	9	fveq2d 6770	. . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (log‘--𝐴) = (log‘𝐴))
11	10	fveqeq2d 6774	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → ((ℑ‘(log‘--𝐴)) = π ↔ (ℑ‘(log‘𝐴)) = π))
12	7, 11	syl5ib 243	. 2 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (-𝐴 ∈ ℝ⁺ → (ℑ‘(log‘𝐴)) = π))
13		logcl 25734	. . . . . . 7 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (log‘𝐴) ∈ ℂ)
14	13	replimd 14918	. . . . . 6 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (log‘𝐴) = ((ℜ‘(log‘𝐴)) + (i · (ℑ‘(log‘𝐴)))))
15	14	fveq2d 6770	. . . . 5 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (exp‘(log‘𝐴)) = (exp‘((ℜ‘(log‘𝐴)) + (i · (ℑ‘(log‘𝐴))))))
16		eflog 25742	. . . . 5 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (exp‘(log‘𝐴)) = 𝐴)
17	13	recld 14915	. . . . . . 7 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (ℜ‘(log‘𝐴)) ∈ ℝ)
18	17	recnd 11013	. . . . . 6 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (ℜ‘(log‘𝐴)) ∈ ℂ)
19		ax-icn 10940	. . . . . . 7 ⊢ i ∈ ℂ
20	13	imcld 14916	. . . . . . . 8 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (ℑ‘(log‘𝐴)) ∈ ℝ)
21	20	recnd 11013	. . . . . . 7 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (ℑ‘(log‘𝐴)) ∈ ℂ)
22		mulcl 10965	. . . . . . 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 15813	. . . . . 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 2786	. . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → 𝐴 = ((exp‘(ℜ‘(log‘𝐴))) · (exp‘(i · (ℑ‘(log‘𝐴))))))
27		oveq2 7275	. . . . . . . 8 ⊢ ((ℑ‘(log‘𝐴)) = π → (i · (ℑ‘(log‘𝐴))) = (i · π))
28	27	fveq2d 6770	. . . . . . 7 ⊢ ((ℑ‘(log‘𝐴)) = π → (exp‘(i · (ℑ‘(log‘𝐴)))) = (exp‘(i · π)))
29		efipi 25640	. . . . . . 7 ⊢ (exp‘(i · π)) = -1
30	28, 29	eqtrdi 2794	. . . . . 6 ⊢ ((ℑ‘(log‘𝐴)) = π → (exp‘(i · (ℑ‘(log‘𝐴)))) = -1)
31	30	oveq2d 7283	. . . . 5 ⊢ ((ℑ‘(log‘𝐴)) = π → ((exp‘(ℜ‘(log‘𝐴))) · (exp‘(i · (ℑ‘(log‘𝐴))))) = ((exp‘(ℜ‘(log‘𝐴))) · -1))
32	31	eqeq2d 2749	. . . 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 244	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → ((ℑ‘(log‘𝐴)) = π → 𝐴 = ((exp‘(ℜ‘(log‘𝐴))) · -1)))
34	17	rpefcld 15824	. . . . . . . . . 10 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (exp‘(ℜ‘(log‘𝐴))) ∈ ℝ⁺)
35	34	rpcnd 12784	. . . . . . . . 9 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (exp‘(ℜ‘(log‘𝐴))) ∈ ℂ)
36		neg1cn 12097	. . . . . . . . 9 ⊢ -1 ∈ ℂ
37		mulcom 10967	. . . . . . . . 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 11437	. . . . . . . 8 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (-1 · (exp‘(ℜ‘(log‘𝐴)))) = -(exp‘(ℜ‘(log‘𝐴))))
40	38, 39	eqtrd 2778	. . . . . . 7 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → ((exp‘(ℜ‘(log‘𝐴))) · -1) = -(exp‘(ℜ‘(log‘𝐴))))
41	40	negeqd 11225	. . . . . 6 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → -((exp‘(ℜ‘(log‘𝐴))) · -1) = --(exp‘(ℜ‘(log‘𝐴))))
42	35	negnegd 11333	. . . . . 6 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → --(exp‘(ℜ‘(log‘𝐴))) = (exp‘(ℜ‘(log‘𝐴))))
43	41, 42	eqtrd 2778	. . . . 5 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → -((exp‘(ℜ‘(log‘𝐴))) · -1) = (exp‘(ℜ‘(log‘𝐴))))
44	43, 34	eqeltrd 2839	. . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → -((exp‘(ℜ‘(log‘𝐴))) · -1) ∈ ℝ⁺)
45		negeq 11223	. . . . 5 ⊢ (𝐴 = ((exp‘(ℜ‘(log‘𝐴))) · -1) → -𝐴 = -((exp‘(ℜ‘(log‘𝐴))) · -1))
46	45	eleq1d 2823	. . . 4 ⊢ (𝐴 = ((exp‘(ℜ‘(log‘𝐴))) · -1) → (-𝐴 ∈ ℝ⁺ ↔ -((exp‘(ℜ‘(log‘𝐴))) · -1) ∈ ℝ⁺))
47	44, 46	syl5ibrcom 246	. . 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 211	1 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ≠ 0) → (-𝐴 ∈ ℝ⁺ ↔ (ℑ‘(log‘𝐴)) = π))

Colors of variables: wff setvar class

Syntax hints: → wi 4 ↔ wb 205 ∧ wa 396 = wceq 1539 ∈ wcel 2106 ≠ wne 2943 ‘cfv 6426 (class class class)co 7267 ℂcc 10879 ℝcr 10880 0cc0 10881 1c1 10882 ici 10883 + caddc 10884 · cmul 10886 -cneg 11216 ℝ⁺crp 12740 ℜcre 14818 ℑcim 14819 expce 15781 πcpi 15786 logclog 25720

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1798 ax-4 1812 ax-5 1913 ax-6 1971 ax-7 2011 ax-8 2108 ax-9 2116 ax-10 2137 ax-11 2154 ax-12 2171 ax-ext 2709 ax-rep 5208 ax-sep 5221 ax-nul 5228 ax-pow 5286 ax-pr 5350 ax-un 7578 ax-inf2 9386 ax-cnex 10937 ax-resscn 10938 ax-1cn 10939 ax-icn 10940 ax-addcl 10941 ax-addrcl 10942 ax-mulcl 10943 ax-mulrcl 10944 ax-mulcom 10945 ax-addass 10946 ax-mulass 10947 ax-distr 10948 ax-i2m1 10949 ax-1ne0 10950 ax-1rid 10951 ax-rnegex 10952 ax-rrecex 10953 ax-cnre 10954 ax-pre-lttri 10955 ax-pre-lttrn 10956 ax-pre-ltadd 10957 ax-pre-mulgt0 10958 ax-pre-sup 10959 ax-addf 10960 ax-mulf 10961

This theorem depends on definitions: df-bi 206 df-an 397 df-or 845 df-3or 1087 df-3an 1088 df-tru 1542 df-fal 1552 df-ex 1783 df-nf 1787 df-sb 2068 df-mo 2540 df-eu 2569 df-clab 2716 df-cleq 2730 df-clel 2816 df-nfc 2889 df-ne 2944 df-nel 3050 df-ral 3069 df-rex 3070 df-reu 3071 df-rmo 3072 df-rab 3073 df-v 3431 df-sbc 3716 df-csb 3832 df-dif 3889 df-un 3891 df-in 3893 df-ss 3903 df-pss 3905 df-nul 4257 df-if 4460 df-pw 4535 df-sn 4562 df-pr 4564 df-tp 4566 df-op 4568 df-uni 4840 df-int 4880 df-iun 4926 df-iin 4927 df-br 5074 df-opab 5136 df-mpt 5157 df-tr 5191 df-id 5484 df-eprel 5490 df-po 5498 df-so 5499 df-fr 5539 df-se 5540 df-we 5541 df-xp 5590 df-rel 5591 df-cnv 5592 df-co 5593 df-dm 5594 df-rn 5595 df-res 5596 df-ima 5597 df-pred 6195 df-ord 6262 df-on 6263 df-lim 6264 df-suc 6265 df-iota 6384 df-fun 6428 df-fn 6429 df-f 6430 df-f1 6431 df-fo 6432 df-f1o 6433 df-fv 6434 df-isom 6435 df-riota 7224 df-ov 7270 df-oprab 7271 df-mpo 7272 df-of 7523 df-om 7703 df-1st 7820 df-2nd 7821 df-supp 7965 df-frecs 8084 df-wrecs 8115 df-recs 8189 df-rdg 8228 df-1o 8284 df-2o 8285 df-er 8485 df-map 8604 df-pm 8605 df-ixp 8673 df-en 8721 df-dom 8722 df-sdom 8723 df-fin 8724 df-fsupp 9116 df-fi 9157 df-sup 9188 df-inf 9189 df-oi 9256 df-card 9707 df-pnf 11021 df-mnf 11022 df-xr 11023 df-ltxr 11024 df-le 11025 df-sub 11217 df-neg 11218 df-div 11643 df-nn 11984 df-2 12046 df-3 12047 df-4 12048 df-5 12049 df-6 12050 df-7 12051 df-8 12052 df-9 12053 df-n0 12244 df-z 12330 df-dec 12448 df-uz 12593 df-q 12699 df-rp 12741 df-xneg 12858 df-xadd 12859 df-xmul 12860 df-ioo 13093 df-ioc 13094 df-ico 13095 df-icc 13096 df-fz 13250 df-fzo 13393 df-fl 13522 df-mod 13600 df-seq 13732 df-exp 13793 df-fac 13998 df-bc 14027 df-hash 14055 df-shft 14788 df-cj 14820 df-re 14821 df-im 14822 df-sqrt 14956 df-abs 14957 df-limsup 15190 df-clim 15207 df-rlim 15208 df-sum 15408 df-ef 15787 df-sin 15789 df-cos 15790 df-pi 15792 df-struct 16858 df-sets 16875 df-slot 16893 df-ndx 16905 df-base 16923 df-ress 16952 df-plusg 16985 df-mulr 16986 df-starv 16987 df-sca 16988 df-vsca 16989 df-ip 16990 df-tset 16991 df-ple 16992 df-ds 16994 df-unif 16995 df-hom 16996 df-cco 16997 df-rest 17143 df-topn 17144 df-0g 17162 df-gsum 17163 df-topgen 17164 df-pt 17165 df-prds 17168 df-xrs 17223 df-qtop 17228 df-imas 17229 df-xps 17231 df-mre 17305 df-mrc 17306 df-acs 17308 df-mgm 18336 df-sgrp 18385 df-mnd 18396 df-submnd 18441 df-mulg 18711 df-cntz 18933 df-cmn 19398 df-psmet 20599 df-xmet 20600 df-met 20601 df-bl 20602 df-mopn 20603 df-fbas 20604 df-fg 20605 df-cnfld 20608 df-top 22053 df-topon 22070 df-topsp 22092 df-bases 22106 df-cld 22180 df-ntr 22181 df-cls 22182 df-nei 22259 df-lp 22297 df-perf 22298 df-cn 22388 df-cnp 22389 df-haus 22476 df-tx 22723 df-hmeo 22916 df-fil 23007 df-fm 23099 df-flim 23100 df-flf 23101 df-xms 23483 df-ms 23484 df-tms 23485 df-cncf 24051 df-limc 25040 df-dv 25041 df-log 25722

This theorem is referenced by: logcj 25771 argimgt0 25777 dvloglem 25813 logf1o2 25815 logrec 25923 ang180lem2 25970 angpieqvdlem2 25989 asinneg 26046

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