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Theorem divdivdivd 10159
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 532 . 2  |-  ( ph  ->  ( B  e.  CC  /\  B  =/=  0 ) )
5 divmuld.3 . . 3  |-  ( ph  ->  C  e.  CC )
6 divdivdivd.7 . . 3  |-  ( ph  ->  C  =/=  0 )
75, 6jca 532 . 2  |-  ( ph  ->  ( C  e.  CC  /\  C  =/=  0 ) )
8 divmuldivd.4 . . 3  |-  ( ph  ->  D  e.  CC )
9 divmuldivd.6 . . 3  |-  ( ph  ->  D  =/=  0 )
108, 9jca 532 . 2  |-  ( ph  ->  ( D  e.  CC  /\  D  =/=  0 ) )
11 divdivdiv 10037 . 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 1219 1  |-  ( ph  ->  ( ( A  /  B )  /  ( C  /  D ) )  =  ( ( A  x.  D )  / 
( B  x.  C
) ) )
Colors of variables: wff setvar class
Syntax hints:    -> wi 4    /\ wa 369    = wceq 1369    e. wcel 1756    =/= wne 2611  (class class class)co 6096   CCcc 9285   0cc0 9287    x. cmul 9292    / cdiv 9998
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1591  ax-4 1602  ax-5 1670  ax-6 1708  ax-7 1728  ax-8 1758  ax-9 1760  ax-10 1775  ax-11 1780  ax-12 1792  ax-13 1943  ax-ext 2423  ax-sep 4418  ax-nul 4426  ax-pow 4475  ax-pr 4536  ax-un 6377  ax-resscn 9344  ax-1cn 9345  ax-icn 9346  ax-addcl 9347  ax-addrcl 9348  ax-mulcl 9349  ax-mulrcl 9350  ax-mulcom 9351  ax-addass 9352  ax-mulass 9353  ax-distr 9354  ax-i2m1 9355  ax-1ne0 9356  ax-1rid 9357  ax-rnegex 9358  ax-rrecex 9359  ax-cnre 9360  ax-pre-lttri 9361  ax-pre-lttrn 9362  ax-pre-ltadd 9363  ax-pre-mulgt0 9364
This theorem depends on definitions:  df-bi 185  df-or 370  df-an 371  df-3or 966  df-3an 967  df-tru 1372  df-ex 1587  df-nf 1590  df-sb 1701  df-eu 2257  df-mo 2258  df-clab 2430  df-cleq 2436  df-clel 2439  df-nfc 2573  df-ne 2613  df-nel 2614  df-ral 2725  df-rex 2726  df-reu 2727  df-rmo 2728  df-rab 2729  df-v 2979  df-sbc 3192  df-csb 3294  df-dif 3336  df-un 3338  df-in 3340  df-ss 3347  df-nul 3643  df-if 3797  df-pw 3867  df-sn 3883  df-pr 3885  df-op 3889  df-uni 4097  df-br 4298  df-opab 4356  df-mpt 4357  df-id 4641  df-po 4646  df-so 4647  df-xp 4851  df-rel 4852  df-cnv 4853  df-co 4854  df-dm 4855  df-rn 4856  df-res 4857  df-ima 4858  df-iota 5386  df-fun 5425  df-fn 5426  df-f 5427  df-f1 5428  df-fo 5429  df-f1o 5430  df-fv 5431  df-riota 6057  df-ov 6099  df-oprab 6100  df-mpt2 6101  df-er 7106  df-en 7316  df-dom 7317  df-sdom 7318  df-pnf 9425  df-mnf 9426  df-xr 9427  df-ltxr 9428  df-le 9429  df-sub 9602  df-neg 9603  df-div 9999
This theorem is referenced by:  pcadd  13956  pnt  22868  wallispilem4  29868  stirlinglem4  29877  stirlinglem10  29883
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