cxplogb - Metamath Proof Explorer

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Theorem cxplogb 25841

Description: Identity law for the general logarithm. (Contributed by AV, 22-May-2020.)

**Assertion**
Ref	Expression
cxplogb	⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (𝐵↑_𝑐(𝐵 log_b 𝑋)) = 𝑋)

**Proof of Theorem cxplogb**
Step	Hyp	Ref	Expression
1		logbval 25821	. . 3 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (𝐵 log_b 𝑋) = ((log‘𝑋) / (log‘𝐵)))
2	1	oveq2d 7271	. 2 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (𝐵↑_𝑐(𝐵 log_b 𝑋)) = (𝐵↑_𝑐((log‘𝑋) / (log‘𝐵))))
3		eldifi 4057	. . . 4 ⊢ (𝐵 ∈ (ℂ ∖ {0, 1}) → 𝐵 ∈ ℂ)
4	3	adantr 480	. . 3 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → 𝐵 ∈ ℂ)
5		eldif 3893	. . . . 5 ⊢ (𝐵 ∈ (ℂ ∖ {0, 1}) ↔ (𝐵 ∈ ℂ ∧ ¬ 𝐵 ∈ {0, 1}))
6		c0ex 10900	. . . . . . . . 9 ⊢ 0 ∈ V
7	6	prid1 4695	. . . . . . . 8 ⊢ 0 ∈ {0, 1}
8		eleq1 2826	. . . . . . . 8 ⊢ (𝐵 = 0 → (𝐵 ∈ {0, 1} ↔ 0 ∈ {0, 1}))
9	7, 8	mpbiri 257	. . . . . . 7 ⊢ (𝐵 = 0 → 𝐵 ∈ {0, 1})
10	9	necon3bi 2969	. . . . . 6 ⊢ (¬ 𝐵 ∈ {0, 1} → 𝐵 ≠ 0)
11	10	adantl 481	. . . . 5 ⊢ ((𝐵 ∈ ℂ ∧ ¬ 𝐵 ∈ {0, 1}) → 𝐵 ≠ 0)
12	5, 11	sylbi 216	. . . 4 ⊢ (𝐵 ∈ (ℂ ∖ {0, 1}) → 𝐵 ≠ 0)
13	12	adantr 480	. . 3 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → 𝐵 ≠ 0)
14		eldif 3893	. . . . . . 7 ⊢ (𝑋 ∈ (ℂ ∖ {0}) ↔ (𝑋 ∈ ℂ ∧ ¬ 𝑋 ∈ {0}))
15	6	snid 4594	. . . . . . . . . 10 ⊢ 0 ∈ {0}
16		eleq1 2826	. . . . . . . . . 10 ⊢ (𝑋 = 0 → (𝑋 ∈ {0} ↔ 0 ∈ {0}))
17	15, 16	mpbiri 257	. . . . . . . . 9 ⊢ (𝑋 = 0 → 𝑋 ∈ {0})
18	17	necon3bi 2969	. . . . . . . 8 ⊢ (¬ 𝑋 ∈ {0} → 𝑋 ≠ 0)
19	18	anim2i 616	. . . . . . 7 ⊢ ((𝑋 ∈ ℂ ∧ ¬ 𝑋 ∈ {0}) → (𝑋 ∈ ℂ ∧ 𝑋 ≠ 0))
20	14, 19	sylbi 216	. . . . . 6 ⊢ (𝑋 ∈ (ℂ ∖ {0}) → (𝑋 ∈ ℂ ∧ 𝑋 ≠ 0))
21		logcl 25629	. . . . . 6 ⊢ ((𝑋 ∈ ℂ ∧ 𝑋 ≠ 0) → (log‘𝑋) ∈ ℂ)
22	20, 21	syl 17	. . . . 5 ⊢ (𝑋 ∈ (ℂ ∖ {0}) → (log‘𝑋) ∈ ℂ)
23	22	adantl 481	. . . 4 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (log‘𝑋) ∈ ℂ)
24	10	anim2i 616	. . . . . . 7 ⊢ ((𝐵 ∈ ℂ ∧ ¬ 𝐵 ∈ {0, 1}) → (𝐵 ∈ ℂ ∧ 𝐵 ≠ 0))
25	5, 24	sylbi 216	. . . . . 6 ⊢ (𝐵 ∈ (ℂ ∖ {0, 1}) → (𝐵 ∈ ℂ ∧ 𝐵 ≠ 0))
26		logcl 25629	. . . . . 6 ⊢ ((𝐵 ∈ ℂ ∧ 𝐵 ≠ 0) → (log‘𝐵) ∈ ℂ)
27	25, 26	syl 17	. . . . 5 ⊢ (𝐵 ∈ (ℂ ∖ {0, 1}) → (log‘𝐵) ∈ ℂ)
28	27	adantr 480	. . . 4 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (log‘𝐵) ∈ ℂ)
29		eldifpr 4590	. . . . . . 7 ⊢ (𝐵 ∈ (ℂ ∖ {0, 1}) ↔ (𝐵 ∈ ℂ ∧ 𝐵 ≠ 0 ∧ 𝐵 ≠ 1))
30	29	biimpi 215	. . . . . 6 ⊢ (𝐵 ∈ (ℂ ∖ {0, 1}) → (𝐵 ∈ ℂ ∧ 𝐵 ≠ 0 ∧ 𝐵 ≠ 1))
31	30	adantr 480	. . . . 5 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (𝐵 ∈ ℂ ∧ 𝐵 ≠ 0 ∧ 𝐵 ≠ 1))
32		logccne0 25639	. . . . 5 ⊢ ((𝐵 ∈ ℂ ∧ 𝐵 ≠ 0 ∧ 𝐵 ≠ 1) → (log‘𝐵) ≠ 0)
33	31, 32	syl 17	. . . 4 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (log‘𝐵) ≠ 0)
34	23, 28, 33	divcld 11681	. . 3 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → ((log‘𝑋) / (log‘𝐵)) ∈ ℂ)
35	4, 13, 34	cxpefd 25772	. 2 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (𝐵↑_𝑐((log‘𝑋) / (log‘𝐵))) = (exp‘(((log‘𝑋) / (log‘𝐵)) · (log‘𝐵))))
36		eldifsn 4717	. . . . . . 7 ⊢ (𝑋 ∈ (ℂ ∖ {0}) ↔ (𝑋 ∈ ℂ ∧ 𝑋 ≠ 0))
37	36, 21	sylbi 216	. . . . . 6 ⊢ (𝑋 ∈ (ℂ ∖ {0}) → (log‘𝑋) ∈ ℂ)
38	37	adantl 481	. . . . 5 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (log‘𝑋) ∈ ℂ)
39	29, 32	sylbi 216	. . . . . 6 ⊢ (𝐵 ∈ (ℂ ∖ {0, 1}) → (log‘𝐵) ≠ 0)
40	39	adantr 480	. . . . 5 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (log‘𝐵) ≠ 0)
41	38, 28, 40	divcan1d 11682	. . . 4 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (((log‘𝑋) / (log‘𝐵)) · (log‘𝐵)) = (log‘𝑋))
42	41	fveq2d 6760	. . 3 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (exp‘(((log‘𝑋) / (log‘𝐵)) · (log‘𝐵))) = (exp‘(log‘𝑋)))
43		eflog 25637	. . . . 5 ⊢ ((𝑋 ∈ ℂ ∧ 𝑋 ≠ 0) → (exp‘(log‘𝑋)) = 𝑋)
44	36, 43	sylbi 216	. . . 4 ⊢ (𝑋 ∈ (ℂ ∖ {0}) → (exp‘(log‘𝑋)) = 𝑋)
45	44	adantl 481	. . 3 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (exp‘(log‘𝑋)) = 𝑋)
46	42, 45	eqtrd 2778	. 2 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (exp‘(((log‘𝑋) / (log‘𝐵)) · (log‘𝐵))) = 𝑋)
47	2, 35, 46	3eqtrd 2782	1 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (𝐵↑_𝑐(𝐵 log_b 𝑋)) = 𝑋)

Colors of variables: wff setvar class

Syntax hints: ¬ wn 3 → wi 4 ∧ wa 395 ∧ w3a 1085 = wceq 1539 ∈ wcel 2108 ≠ wne 2942 ∖ cdif 3880 {csn 4558 {cpr 4560 ‘cfv 6418 (class class class)co 7255 ℂcc 10800 0cc0 10802 1c1 10803 · cmul 10807 / cdiv 11562 expce 15699 logclog 25615 ↑_𝑐ccxp 25616 log_b clogb 25819

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1799 ax-4 1813 ax-5 1914 ax-6 1972 ax-7 2012 ax-8 2110 ax-9 2118 ax-10 2139 ax-11 2156 ax-12 2173 ax-ext 2709 ax-rep 5205 ax-sep 5218 ax-nul 5225 ax-pow 5283 ax-pr 5347 ax-un 7566 ax-inf2 9329 ax-cnex 10858 ax-resscn 10859 ax-1cn 10860 ax-icn 10861 ax-addcl 10862 ax-addrcl 10863 ax-mulcl 10864 ax-mulrcl 10865 ax-mulcom 10866 ax-addass 10867 ax-mulass 10868 ax-distr 10869 ax-i2m1 10870 ax-1ne0 10871 ax-1rid 10872 ax-rnegex 10873 ax-rrecex 10874 ax-cnre 10875 ax-pre-lttri 10876 ax-pre-lttrn 10877 ax-pre-ltadd 10878 ax-pre-mulgt0 10879 ax-pre-sup 10880 ax-addf 10881 ax-mulf 10882

This theorem depends on definitions: df-bi 206 df-an 396 df-or 844 df-3or 1086 df-3an 1087 df-tru 1542 df-fal 1552 df-ex 1784 df-nf 1788 df-sb 2069 df-mo 2540 df-eu 2569 df-clab 2716 df-cleq 2730 df-clel 2817 df-nfc 2888 df-ne 2943 df-nel 3049 df-ral 3068 df-rex 3069 df-reu 3070 df-rmo 3071 df-rab 3072 df-v 3424 df-sbc 3712 df-csb 3829 df-dif 3886 df-un 3888 df-in 3890 df-ss 3900 df-pss 3902 df-nul 4254 df-if 4457 df-pw 4532 df-sn 4559 df-pr 4561 df-tp 4563 df-op 4565 df-uni 4837 df-int 4877 df-iun 4923 df-iin 4924 df-br 5071 df-opab 5133 df-mpt 5154 df-tr 5188 df-id 5480 df-eprel 5486 df-po 5494 df-so 5495 df-fr 5535 df-se 5536 df-we 5537 df-xp 5586 df-rel 5587 df-cnv 5588 df-co 5589 df-dm 5590 df-rn 5591 df-res 5592 df-ima 5593 df-pred 6191 df-ord 6254 df-on 6255 df-lim 6256 df-suc 6257 df-iota 6376 df-fun 6420 df-fn 6421 df-f 6422 df-f1 6423 df-fo 6424 df-f1o 6425 df-fv 6426 df-isom 6427 df-riota 7212 df-ov 7258 df-oprab 7259 df-mpo 7260 df-of 7511 df-om 7688 df-1st 7804 df-2nd 7805 df-supp 7949 df-frecs 8068 df-wrecs 8099 df-recs 8173 df-rdg 8212 df-1o 8267 df-2o 8268 df-er 8456 df-map 8575 df-pm 8576 df-ixp 8644 df-en 8692 df-dom 8693 df-sdom 8694 df-fin 8695 df-fsupp 9059 df-fi 9100 df-sup 9131 df-inf 9132 df-oi 9199 df-card 9628 df-pnf 10942 df-mnf 10943 df-xr 10944 df-ltxr 10945 df-le 10946 df-sub 11137 df-neg 11138 df-div 11563 df-nn 11904 df-2 11966 df-3 11967 df-4 11968 df-5 11969 df-6 11970 df-7 11971 df-8 11972 df-9 11973 df-n0 12164 df-z 12250 df-dec 12367 df-uz 12512 df-q 12618 df-rp 12660 df-xneg 12777 df-xadd 12778 df-xmul 12779 df-ioo 13012 df-ioc 13013 df-ico 13014 df-icc 13015 df-fz 13169 df-fzo 13312 df-fl 13440 df-mod 13518 df-seq 13650 df-exp 13711 df-fac 13916 df-bc 13945 df-hash 13973 df-shft 14706 df-cj 14738 df-re 14739 df-im 14740 df-sqrt 14874 df-abs 14875 df-limsup 15108 df-clim 15125 df-rlim 15126 df-sum 15326 df-ef 15705 df-sin 15707 df-cos 15708 df-pi 15710 df-struct 16776 df-sets 16793 df-slot 16811 df-ndx 16823 df-base 16841 df-ress 16868 df-plusg 16901 df-mulr 16902 df-starv 16903 df-sca 16904 df-vsca 16905 df-ip 16906 df-tset 16907 df-ple 16908 df-ds 16910 df-unif 16911 df-hom 16912 df-cco 16913 df-rest 17050 df-topn 17051 df-0g 17069 df-gsum 17070 df-topgen 17071 df-pt 17072 df-prds 17075 df-xrs 17130 df-qtop 17135 df-imas 17136 df-xps 17138 df-mre 17212 df-mrc 17213 df-acs 17215 df-mgm 18241 df-sgrp 18290 df-mnd 18301 df-submnd 18346 df-mulg 18616 df-cntz 18838 df-cmn 19303 df-psmet 20502 df-xmet 20503 df-met 20504 df-bl 20505 df-mopn 20506 df-fbas 20507 df-fg 20508 df-cnfld 20511 df-top 21951 df-topon 21968 df-topsp 21990 df-bases 22004 df-cld 22078 df-ntr 22079 df-cls 22080 df-nei 22157 df-lp 22195 df-perf 22196 df-cn 22286 df-cnp 22287 df-haus 22374 df-tx 22621 df-hmeo 22814 df-fil 22905 df-fm 22997 df-flim 22998 df-flf 22999 df-xms 23381 df-ms 23382 df-tms 23383 df-cncf 23947 df-limc 24935 df-dv 24936 df-log 25617 df-cxp 25618 df-logb 25820

This theorem is referenced by: relogbcxpb 25842 logbgcd1irr 25849 sqrt2cxp2logb9e3 25854 aks4d1p1p4 40007 aks4d1p6 40017 fllogbd 45794 nnpw2blen 45814 dignn0ldlem 45836

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