Theorem rplogbchbase 14529

Description: Change of base for logarithms. Property in [Cohen4] p. 367. (Contributed by AV, 11-Jun-2020.)

Assertion

Ref	Expression
rplogbchbase	|- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> ( A logb X ) = ( ( B logb X ) / ( B logb A ) ) )

Proof of Theorem rplogbchbase

Step	Hyp	Ref	Expression
1		simp3 999	. . . . 5 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> X e. RR+ )
2	1	relogcld 14464	. . . 4 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> ( log ` X ) e. RR )
3	2	recnd 7989	. . 3 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> ( log ` X ) e. CC )
4		simp1l 1021	. . . . 5 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> A e. RR+ )
5	4	relogcld 14464	. . . 4 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> ( log ` A ) e. RR )
6	5	recnd 7989	. . 3 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> ( log ` A ) e. CC )
7		simp2l 1023	. . . . 5 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> B e. RR+ )
8	7	relogcld 14464	. . . 4 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> ( log ` B ) e. RR )
9	8	recnd 7989	. . 3 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> ( log ` B ) e. CC )
10		simp1r 1022	. . . 4 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> A # 1 )
11	4, 10	logrpap0d 14460	. . 3 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> ( log ` A ) # 0 )
12		simp2r 1024	. . . 4 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> B # 1 )
13	7, 12	logrpap0d 14460	. . 3 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> ( log ` B ) # 0 )
14	3, 6, 9, 11, 13	divcanap7d 8779	. 2 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> ( ( ( log ` X ) / ( log ` B ) ) / ( ( log ` A ) / ( log ` B ) ) ) = ( ( log ` X ) / ( log ` A ) ) )
15		rplogbval 14524	. . . 4 |- ( ( B e. RR+ /\ B # 1 /\ X e. RR+ ) -> ( B logb X ) = ( ( log ` X ) / ( log ` B ) ) )
16	7, 12, 1, 15	syl3anc 1238	. . 3 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> ( B logb X ) = ( ( log ` X ) / ( log ` B ) ) )
17		rplogbval 14524	. . . 4 |- ( ( B e. RR+ /\ B # 1 /\ A e. RR+ ) -> ( B logb A ) = ( ( log ` A ) / ( log ` B ) ) )
18	7, 12, 4, 17	syl3anc 1238	. . 3 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> ( B logb A ) = ( ( log ` A ) / ( log ` B ) ) )
19	16, 18	oveq12d 5896	. 2 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> ( ( B logb X ) / ( B logb A ) ) = ( ( ( log ` X ) / ( log ` B ) ) / ( ( log ` A ) / ( log ` B ) ) ) )
20		rplogbval 14524	. . 3 |- ( ( A e. RR+ /\ A # 1 /\ X e. RR+ ) -> ( A logb X ) = ( ( log ` X ) / ( log ` A ) ) )
21	4, 10, 1, 20	syl3anc 1238	. 2 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> ( A logb X ) = ( ( log ` X ) / ( log ` A ) ) )
22	14, 19, 21	3eqtr4rd 2221	1 |- ( ( ( A e. RR+ /\ A # 1 ) /\ ( B e. RR+ /\ B # 1 ) /\ X e. RR+ ) -> ( A logb X ) = ( ( B logb X ) / ( B logb A ) ) )

Syntax hints:   -> wi 4   /\ wa 104   /\ w3a 978   = wceq 1353   e. wcel 2148   class class class wbr 4005   ` cfv 5218  (class class class)co 5878   1c1 7815   # cap 8541   / cdiv 8632   RR+crp 9656   logclog 14438   log_b clogb 14522

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 614  ax-in2 615  ax-io 709  ax-5 1447  ax-7 1448  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-8 1504  ax-10 1505  ax-11 1506  ax-i12 1507  ax-bndl 1509  ax-4 1510  ax-17 1526  ax-i9 1530  ax-ial 1534  ax-i5r 1535  ax-13 2150  ax-14 2151  ax-ext 2159  ax-coll 4120  ax-sep 4123  ax-nul 4131  ax-pow 4176  ax-pr 4211  ax-un 4435  ax-setind 4538  ax-iinf 4589  ax-cnex 7905  ax-resscn 7906  ax-1cn 7907  ax-1re 7908  ax-icn 7909  ax-addcl 7910  ax-addrcl 7911  ax-mulcl 7912  ax-mulrcl 7913  ax-addcom 7914  ax-mulcom 7915  ax-addass 7916  ax-mulass 7917  ax-distr 7918  ax-i2m1 7919  ax-0lt1 7920  ax-1rid 7921  ax-0id 7922  ax-rnegex 7923  ax-precex 7924  ax-cnre 7925  ax-pre-ltirr 7926  ax-pre-ltwlin 7927  ax-pre-lttrn 7928  ax-pre-apti 7929  ax-pre-ltadd 7930  ax-pre-mulgt0 7931  ax-pre-mulext 7932  ax-arch 7933  ax-caucvg 7934  ax-pre-suploc 7935  ax-addf 7936  ax-mulf 7937

This theorem depends on definitions:  df-bi 117  df-stab 831  df-dc 835  df-3or 979  df-3an 980  df-tru 1356  df-fal 1359  df-nf 1461  df-sb 1763  df-eu 2029  df-mo 2030  df-clab 2164  df-cleq 2170  df-clel 2173  df-nfc 2308  df-ne 2348  df-nel 2443  df-ral 2460  df-rex 2461  df-reu 2462  df-rmo 2463  df-rab 2464  df-v 2741  df-sbc 2965  df-csb 3060  df-dif 3133  df-un 3135  df-in 3137  df-ss 3144  df-nul 3425  df-if 3537  df-pw 3579  df-sn 3600  df-pr 3601  df-op 3603  df-uni 3812  df-int 3847  df-iun 3890  df-disj 3983  df-br 4006  df-opab 4067  df-mpt 4068  df-tr 4104  df-id 4295  df-po 4298  df-iso 4299  df-iord 4368  df-on 4370  df-ilim 4371  df-suc 4373  df-iom 4592  df-xp 4634  df-rel 4635  df-cnv 4636  df-co 4637  df-dm 4638  df-rn 4639  df-res 4640  df-ima 4641  df-iota 5180  df-fun 5220  df-fn 5221  df-f 5222  df-f1 5223  df-fo 5224  df-f1o 5225  df-fv 5226  df-isom 5227  df-riota 5834  df-ov 5881  df-oprab 5882  df-mpo 5883  df-of 6086  df-1st 6144  df-2nd 6145  df-recs 6309  df-irdg 6374  df-frec 6395  df-1o 6420  df-oadd 6424  df-er 6538  df-map 6653  df-pm 6654  df-en 6744  df-dom 6745  df-fin 6746  df-sup 6986  df-inf 6987  df-pnf 7997  df-mnf 7998  df-xr 7999  df-ltxr 8000  df-le 8001  df-sub 8133  df-neg 8134  df-reap 8535  df-ap 8542  df-div 8633  df-inn 8923  df-2 8981  df-3 8982  df-4 8983  df-n0 9180  df-z 9257  df-uz 9532  df-q 9623  df-rp 9657  df-xneg 9775  df-xadd 9776  df-ioo 9895  df-ico 9897  df-icc 9898  df-fz 10012  df-fzo 10146  df-seqfrec 10449  df-exp 10523  df-fac 10709  df-bc 10731  df-ihash 10759  df-shft 10827  df-cj 10854  df-re 10855  df-im 10856  df-rsqrt 11010  df-abs 11011  df-clim 11290  df-sumdc 11365  df-ef 11659  df-e 11660  df-rest 12696  df-topgen 12715  df-psmet 13594  df-xmet 13595  df-met 13596  df-bl 13597  df-mopn 13598  df-top 13659  df-topon 13672  df-bases 13704  df-ntr 13757  df-cn 13849  df-cnp 13850  df-tx 13914  df-cncf 14219  df-limced 14286  df-dvap 14287  df-relog 14440  df-logb 14523

This theorem is referenced by: (None)