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Theorem divdivdivd 9463
Description: Division of two ratios. Theorem I.15 of [Apostol] p. 18. (Contributed by Mario Carneiro, 27-May-2016.)
Hypotheses
Ref Expression
div1d.1  |-  ( ph  ->  A  e.  CC )
divcld.2  |-  ( ph  ->  B  e.  CC )
divmuld.3  |-  ( ph  ->  C  e.  CC )
divmuldivd.4  |-  ( ph  ->  D  e.  CC )
divmuldivd.5  |-  ( ph  ->  B  =/=  0 )
divmuldivd.6  |-  ( ph  ->  D  =/=  0 )
divdivdivd.7  |-  ( ph  ->  C  =/=  0 )
Assertion
Ref Expression
divdivdivd  |-  ( ph  ->  ( ( A  /  B )  /  ( C  /  D ) )  =  ( ( A  x.  D )  / 
( B  x.  C
) ) )

Proof of Theorem divdivdivd
StepHypRef Expression
1 div1d.1 . 2  |-  ( ph  ->  A  e.  CC )
2 divcld.2 . . 3  |-  ( ph  ->  B  e.  CC )
3 divmuldivd.5 . . 3  |-  ( ph  ->  B  =/=  0 )
42, 3jca 520 . 2  |-  ( ph  ->  ( B  e.  CC  /\  B  =/=  0 ) )
5 divmuld.3 . . 3  |-  ( ph  ->  C  e.  CC )
6 divdivdivd.7 . . 3  |-  ( ph  ->  C  =/=  0 )
75, 6jca 520 . 2  |-  ( ph  ->  ( C  e.  CC  /\  C  =/=  0 ) )
8 divmuldivd.4 . . 3  |-  ( ph  ->  D  e.  CC )
9 divmuldivd.6 . . 3  |-  ( ph  ->  D  =/=  0 )
108, 9jca 520 . 2  |-  ( ph  ->  ( D  e.  CC  /\  D  =/=  0 ) )
11 divdivdiv 9341 . 2  |-  ( ( ( A  e.  CC  /\  ( B  e.  CC  /\  B  =/=  0 ) )  /\  ( ( C  e.  CC  /\  C  =/=  0 )  /\  ( D  e.  CC  /\  D  =/=  0 ) ) )  ->  (
( A  /  B
)  /  ( C  /  D ) )  =  ( ( A  x.  D )  / 
( B  x.  C
) ) )
121, 4, 7, 10, 11syl22anc 1188 1  |-  ( ph  ->  ( ( A  /  B )  /  ( C  /  D ) )  =  ( ( A  x.  D )  / 
( B  x.  C
) ) )
Colors of variables: wff set class
Syntax hints:    -> wi 6    /\ wa 360    = wceq 1619    e. wcel 1621    =/= wne 2412  (class class class)co 5710   CCcc 8615   0cc0 8617    x. cmul 8622    / cdiv 9303
This theorem is referenced by:  pcadd  12811  pnt  20595
This theorem was proved from axioms:  ax-1 7  ax-2 8  ax-3 9  ax-mp 10  ax-5 1533  ax-6 1534  ax-7 1535  ax-gen 1536  ax-8 1623  ax-11 1624  ax-13 1625  ax-14 1626  ax-17 1628  ax-12o 1664  ax-10 1678  ax-9 1684  ax-4 1692  ax-16 1926  ax-ext 2234  ax-sep 4038  ax-nul 4046  ax-pow 4082  ax-pr 4108  ax-un 4403  ax-resscn 8674  ax-1cn 8675  ax-icn 8676  ax-addcl 8677  ax-addrcl 8678  ax-mulcl 8679  ax-mulrcl 8680  ax-mulcom 8681  ax-addass 8682  ax-mulass 8683  ax-distr 8684  ax-i2m1 8685  ax-1ne0 8686  ax-1rid 8687  ax-rnegex 8688  ax-rrecex 8689  ax-cnre 8690  ax-pre-lttri 8691  ax-pre-lttrn 8692  ax-pre-ltadd 8693  ax-pre-mulgt0 8694
This theorem depends on definitions:  df-bi 179  df-or 361  df-an 362  df-3or 940  df-3an 941  df-tru 1315  df-ex 1538  df-nf 1540  df-sb 1883  df-eu 2118  df-mo 2119  df-clab 2240  df-cleq 2246  df-clel 2249  df-nfc 2374  df-ne 2414  df-nel 2415  df-ral 2513  df-rex 2514  df-reu 2515  df-rab 2516  df-v 2729  df-sbc 2922  df-csb 3010  df-dif 3081  df-un 3083  df-in 3085  df-ss 3089  df-nul 3363  df-if 3471  df-pw 3532  df-sn 3550  df-pr 3551  df-op 3553  df-uni 3728  df-br 3921  df-opab 3975  df-mpt 3976  df-id 4202  df-po 4207  df-so 4208  df-xp 4594  df-rel 4595  df-cnv 4596  df-co 4597  df-dm 4598  df-rn 4599  df-res 4600  df-ima 4601  df-fun 4602  df-fn 4603  df-f 4604  df-f1 4605  df-fo 4606  df-f1o 4607  df-fv 4608  df-ov 5713  df-oprab 5714  df-mpt2 5715  df-iota 6143  df-riota 6190  df-er 6546  df-en 6750  df-dom 6751  df-sdom 6752  df-pnf 8749  df-mnf 8750  df-xr 8751  df-ltxr 8752  df-le 8753  df-sub 8919  df-neg 8920  df-div 9304
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