cxplogb - Metamath Proof Explorer

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Theorem cxplogb 24815

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 24795	. . 3 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (𝐵 log_b 𝑋) = ((log‘𝑋) / (log‘𝐵)))
2	1	oveq2d 6858	. 2 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (𝐵↑_𝑐(𝐵 log_b 𝑋)) = (𝐵↑_𝑐((log‘𝑋) / (log‘𝐵))))
3		eldifi 3894	. . . 4 ⊢ (𝐵 ∈ (ℂ ∖ {0, 1}) → 𝐵 ∈ ℂ)
4	3	adantr 472	. . 3 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → 𝐵 ∈ ℂ)
5		eldif 3742	. . . . 5 ⊢ (𝐵 ∈ (ℂ ∖ {0, 1}) ↔ (𝐵 ∈ ℂ ∧ ¬ 𝐵 ∈ {0, 1}))
6		c0ex 10287	. . . . . . . . 9 ⊢ 0 ∈ V
7	6	prid1 4452	. . . . . . . 8 ⊢ 0 ∈ {0, 1}
8		eleq1 2832	. . . . . . . 8 ⊢ (𝐵 = 0 → (𝐵 ∈ {0, 1} ↔ 0 ∈ {0, 1}))
9	7, 8	mpbiri 249	. . . . . . 7 ⊢ (𝐵 = 0 → 𝐵 ∈ {0, 1})
10	9	necon3bi 2963	. . . . . 6 ⊢ (¬ 𝐵 ∈ {0, 1} → 𝐵 ≠ 0)
11	10	adantl 473	. . . . 5 ⊢ ((𝐵 ∈ ℂ ∧ ¬ 𝐵 ∈ {0, 1}) → 𝐵 ≠ 0)
12	5, 11	sylbi 208	. . . 4 ⊢ (𝐵 ∈ (ℂ ∖ {0, 1}) → 𝐵 ≠ 0)
13	12	adantr 472	. . 3 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → 𝐵 ≠ 0)
14		eldif 3742	. . . . . . 7 ⊢ (𝑋 ∈ (ℂ ∖ {0}) ↔ (𝑋 ∈ ℂ ∧ ¬ 𝑋 ∈ {0}))
15	6	snid 4366	. . . . . . . . . 10 ⊢ 0 ∈ {0}
16		eleq1 2832	. . . . . . . . . 10 ⊢ (𝑋 = 0 → (𝑋 ∈ {0} ↔ 0 ∈ {0}))
17	15, 16	mpbiri 249	. . . . . . . . 9 ⊢ (𝑋 = 0 → 𝑋 ∈ {0})
18	17	necon3bi 2963	. . . . . . . 8 ⊢ (¬ 𝑋 ∈ {0} → 𝑋 ≠ 0)
19	18	anim2i 610	. . . . . . 7 ⊢ ((𝑋 ∈ ℂ ∧ ¬ 𝑋 ∈ {0}) → (𝑋 ∈ ℂ ∧ 𝑋 ≠ 0))
20	14, 19	sylbi 208	. . . . . 6 ⊢ (𝑋 ∈ (ℂ ∖ {0}) → (𝑋 ∈ ℂ ∧ 𝑋 ≠ 0))
21		logcl 24606	. . . . . 6 ⊢ ((𝑋 ∈ ℂ ∧ 𝑋 ≠ 0) → (log‘𝑋) ∈ ℂ)
22	20, 21	syl 17	. . . . 5 ⊢ (𝑋 ∈ (ℂ ∖ {0}) → (log‘𝑋) ∈ ℂ)
23	22	adantl 473	. . . 4 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (log‘𝑋) ∈ ℂ)
24	10	anim2i 610	. . . . . . 7 ⊢ ((𝐵 ∈ ℂ ∧ ¬ 𝐵 ∈ {0, 1}) → (𝐵 ∈ ℂ ∧ 𝐵 ≠ 0))
25	5, 24	sylbi 208	. . . . . 6 ⊢ (𝐵 ∈ (ℂ ∖ {0, 1}) → (𝐵 ∈ ℂ ∧ 𝐵 ≠ 0))
26		logcl 24606	. . . . . 6 ⊢ ((𝐵 ∈ ℂ ∧ 𝐵 ≠ 0) → (log‘𝐵) ∈ ℂ)
27	25, 26	syl 17	. . . . 5 ⊢ (𝐵 ∈ (ℂ ∖ {0, 1}) → (log‘𝐵) ∈ ℂ)
28	27	adantr 472	. . . 4 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (log‘𝐵) ∈ ℂ)
29		eldifpr 4362	. . . . . . 7 ⊢ (𝐵 ∈ (ℂ ∖ {0, 1}) ↔ (𝐵 ∈ ℂ ∧ 𝐵 ≠ 0 ∧ 𝐵 ≠ 1))
30	29	biimpi 207	. . . . . 6 ⊢ (𝐵 ∈ (ℂ ∖ {0, 1}) → (𝐵 ∈ ℂ ∧ 𝐵 ≠ 0 ∧ 𝐵 ≠ 1))
31	30	adantr 472	. . . . 5 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (𝐵 ∈ ℂ ∧ 𝐵 ≠ 0 ∧ 𝐵 ≠ 1))
32		logccne0 24616	. . . . 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 11055	. . 3 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → ((log‘𝑋) / (log‘𝐵)) ∈ ℂ)
35	4, 13, 34	cxpefd 24749	. 2 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (𝐵↑_𝑐((log‘𝑋) / (log‘𝐵))) = (exp‘(((log‘𝑋) / (log‘𝐵)) · (log‘𝐵))))
36		eldifsn 4472	. . . . . . 7 ⊢ (𝑋 ∈ (ℂ ∖ {0}) ↔ (𝑋 ∈ ℂ ∧ 𝑋 ≠ 0))
37	36, 21	sylbi 208	. . . . . 6 ⊢ (𝑋 ∈ (ℂ ∖ {0}) → (log‘𝑋) ∈ ℂ)
38	37	adantl 473	. . . . 5 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (log‘𝑋) ∈ ℂ)
39	29, 32	sylbi 208	. . . . . 6 ⊢ (𝐵 ∈ (ℂ ∖ {0, 1}) → (log‘𝐵) ≠ 0)
40	39	adantr 472	. . . . 5 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (log‘𝐵) ≠ 0)
41	38, 28, 40	divcan1d 11056	. . . 4 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (((log‘𝑋) / (log‘𝐵)) · (log‘𝐵)) = (log‘𝑋))
42	41	fveq2d 6379	. . 3 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (exp‘(((log‘𝑋) / (log‘𝐵)) · (log‘𝐵))) = (exp‘(log‘𝑋)))
43		eflog 24614	. . . . 5 ⊢ ((𝑋 ∈ ℂ ∧ 𝑋 ≠ 0) → (exp‘(log‘𝑋)) = 𝑋)
44	36, 43	sylbi 208	. . . 4 ⊢ (𝑋 ∈ (ℂ ∖ {0}) → (exp‘(log‘𝑋)) = 𝑋)
45	44	adantl 473	. . 3 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (exp‘(log‘𝑋)) = 𝑋)
46	42, 45	eqtrd 2799	. 2 ⊢ ((𝐵 ∈ (ℂ ∖ {0, 1}) ∧ 𝑋 ∈ (ℂ ∖ {0})) → (exp‘(((log‘𝑋) / (log‘𝐵)) · (log‘𝐵))) = 𝑋)
47	2, 35, 46	3eqtrd 2803	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 384 ∧ w3a 1107 = wceq 1652 ∈ wcel 2155 ≠ wne 2937 ∖ cdif 3729 {csn 4334 {cpr 4336 ‘cfv 6068 (class class class)co 6842 ℂcc 10187 0cc0 10189 1c1 10190 · cmul 10194 / cdiv 10938 expce 15076 logclog 24592 ↑_𝑐ccxp 24593 log_b clogb 24793

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1890 ax-4 1904 ax-5 2005 ax-6 2070 ax-7 2105 ax-8 2157 ax-9 2164 ax-10 2183 ax-11 2198 ax-12 2211 ax-13 2352 ax-ext 2743 ax-rep 4930 ax-sep 4941 ax-nul 4949 ax-pow 5001 ax-pr 5062 ax-un 7147 ax-inf2 8753 ax-cnex 10245 ax-resscn 10246 ax-1cn 10247 ax-icn 10248 ax-addcl 10249 ax-addrcl 10250 ax-mulcl 10251 ax-mulrcl 10252 ax-mulcom 10253 ax-addass 10254 ax-mulass 10255 ax-distr 10256 ax-i2m1 10257 ax-1ne0 10258 ax-1rid 10259 ax-rnegex 10260 ax-rrecex 10261 ax-cnre 10262 ax-pre-lttri 10263 ax-pre-lttrn 10264 ax-pre-ltadd 10265 ax-pre-mulgt0 10266 ax-pre-sup 10267 ax-addf 10268 ax-mulf 10269

This theorem depends on definitions: df-bi 198 df-an 385 df-or 874 df-3or 1108 df-3an 1109 df-tru 1656 df-fal 1666 df-ex 1875 df-nf 1879 df-sb 2063 df-mo 2565 df-eu 2582 df-clab 2752 df-cleq 2758 df-clel 2761 df-nfc 2896 df-ne 2938 df-nel 3041 df-ral 3060 df-rex 3061 df-reu 3062 df-rmo 3063 df-rab 3064 df-v 3352 df-sbc 3597 df-csb 3692 df-dif 3735 df-un 3737 df-in 3739 df-ss 3746 df-pss 3748 df-nul 4080 df-if 4244 df-pw 4317 df-sn 4335 df-pr 4337 df-tp 4339 df-op 4341 df-uni 4595 df-int 4634 df-iun 4678 df-iin 4679 df-br 4810 df-opab 4872 df-mpt 4889 df-tr 4912 df-id 5185 df-eprel 5190 df-po 5198 df-so 5199 df-fr 5236 df-se 5237 df-we 5238 df-xp 5283 df-rel 5284 df-cnv 5285 df-co 5286 df-dm 5287 df-rn 5288 df-res 5289 df-ima 5290 df-pred 5865 df-ord 5911 df-on 5912 df-lim 5913 df-suc 5914 df-iota 6031 df-fun 6070 df-fn 6071 df-f 6072 df-f1 6073 df-fo 6074 df-f1o 6075 df-fv 6076 df-isom 6077 df-riota 6803 df-ov 6845 df-oprab 6846 df-mpt2 6847 df-of 7095 df-om 7264 df-1st 7366 df-2nd 7367 df-supp 7498 df-wrecs 7610 df-recs 7672 df-rdg 7710 df-1o 7764 df-2o 7765 df-oadd 7768 df-er 7947 df-map 8062 df-pm 8063 df-ixp 8114 df-en 8161 df-dom 8162 df-sdom 8163 df-fin 8164 df-fsupp 8483 df-fi 8524 df-sup 8555 df-inf 8556 df-oi 8622 df-card 9016 df-cda 9243 df-pnf 10330 df-mnf 10331 df-xr 10332 df-ltxr 10333 df-le 10334 df-sub 10522 df-neg 10523 df-div 10939 df-nn 11275 df-2 11335 df-3 11336 df-4 11337 df-5 11338 df-6 11339 df-7 11340 df-8 11341 df-9 11342 df-n0 11539 df-z 11625 df-dec 11741 df-uz 11887 df-q 11990 df-rp 12029 df-xneg 12146 df-xadd 12147 df-xmul 12148 df-ioo 12381 df-ioc 12382 df-ico 12383 df-icc 12384 df-fz 12534 df-fzo 12674 df-fl 12801 df-mod 12877 df-seq 13009 df-exp 13068 df-fac 13265 df-bc 13294 df-hash 13322 df-shft 14094 df-cj 14126 df-re 14127 df-im 14128 df-sqrt 14262 df-abs 14263 df-limsup 14489 df-clim 14506 df-rlim 14507 df-sum 14704 df-ef 15082 df-sin 15084 df-cos 15085 df-pi 15087 df-struct 16134 df-ndx 16135 df-slot 16136 df-base 16138 df-sets 16139 df-ress 16140 df-plusg 16229 df-mulr 16230 df-starv 16231 df-sca 16232 df-vsca 16233 df-ip 16234 df-tset 16235 df-ple 16236 df-ds 16238 df-unif 16239 df-hom 16240 df-cco 16241 df-rest 16351 df-topn 16352 df-0g 16370 df-gsum 16371 df-topgen 16372 df-pt 16373 df-prds 16376 df-xrs 16430 df-qtop 16435 df-imas 16436 df-xps 16438 df-mre 16514 df-mrc 16515 df-acs 16517 df-mgm 17510 df-sgrp 17552 df-mnd 17563 df-submnd 17604 df-mulg 17810 df-cntz 18015 df-cmn 18461 df-psmet 20011 df-xmet 20012 df-met 20013 df-bl 20014 df-mopn 20015 df-fbas 20016 df-fg 20017 df-cnfld 20020 df-top 20978 df-topon 20995 df-topsp 21017 df-bases 21030 df-cld 21103 df-ntr 21104 df-cls 21105 df-nei 21182 df-lp 21220 df-perf 21221 df-cn 21311 df-cnp 21312 df-haus 21399 df-tx 21645 df-hmeo 21838 df-fil 21929 df-fm 22021 df-flim 22022 df-flf 22023 df-xms 22404 df-ms 22405 df-tms 22406 df-cncf 22960 df-limc 23921 df-dv 23922 df-log 24594 df-cxp 24595 df-logb 24794

This theorem is referenced by: relogbcxpb 24816 fllogbd 42955 nnpw2blen 42975 dignn0ldlem 42997

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