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Theorem xmulpnf1n 11253
Description: Multiplication by plus infinity on the right, for negative input. (Contributed by Mario Carneiro, 20-Aug-2015.)
Assertion
Ref Expression
xmulpnf1n  |-  ( ( A  e.  RR*  /\  A  <  0 )  ->  ( A xe +oo )  = -oo )

Proof of Theorem xmulpnf1n
StepHypRef Expression
1 simpl 457 . . . . 5  |-  ( ( A  e.  RR*  /\  A  <  0 )  ->  A  e.  RR* )
2 pnfxr 11104 . . . . 5  |- +oo  e.  RR*
3 xmulneg1 11244 . . . . 5  |-  ( ( A  e.  RR*  /\ +oo  e.  RR* )  ->  (  -e A xe +oo )  =  -e ( A xe +oo ) )
41, 2, 3sylancl 662 . . . 4  |-  ( ( A  e.  RR*  /\  A  <  0 )  ->  (  -e A xe +oo )  =  -e ( A xe +oo ) )
5 xnegcl 11195 . . . . . 6  |-  ( A  e.  RR*  ->  -e
A  e.  RR* )
65adantr 465 . . . . 5  |-  ( ( A  e.  RR*  /\  A  <  0 )  ->  -e
A  e.  RR* )
7 xlt0neg1 11201 . . . . . 6  |-  ( A  e.  RR*  ->  ( A  <  0  <->  0  <  -e A ) )
87biimpa 484 . . . . 5  |-  ( ( A  e.  RR*  /\  A  <  0 )  ->  0  <  -e A )
9 xmulpnf1 11249 . . . . 5  |-  ( ( 
-e A  e. 
RR*  /\  0  <  -e A )  -> 
(  -e A xe +oo )  = +oo )
106, 8, 9syl2anc 661 . . . 4  |-  ( ( A  e.  RR*  /\  A  <  0 )  ->  (  -e A xe +oo )  = +oo )
114, 10eqtr3d 2477 . . 3  |-  ( ( A  e.  RR*  /\  A  <  0 )  ->  -e
( A xe +oo )  = +oo )
12 xnegmnf 11192 . . 3  |-  -e -oo  = +oo
1311, 12syl6eqr 2493 . 2  |-  ( ( A  e.  RR*  /\  A  <  0 )  ->  -e
( A xe +oo )  =  -e -oo )
14 xmulcl 11248 . . . 4  |-  ( ( A  e.  RR*  /\ +oo  e.  RR* )  ->  ( A xe +oo )  e.  RR* )
151, 2, 14sylancl 662 . . 3  |-  ( ( A  e.  RR*  /\  A  <  0 )  ->  ( A xe +oo )  e.  RR* )
16 mnfxr 11106 . . 3  |- -oo  e.  RR*
17 xneg11 11197 . . 3  |-  ( ( ( A xe +oo )  e.  RR*  /\ -oo  e.  RR* )  ->  (  -e ( A xe +oo )  = 
-e -oo  <->  ( A xe +oo )  = -oo ) )
1815, 16, 17sylancl 662 . 2  |-  ( ( A  e.  RR*  /\  A  <  0 )  ->  (  -e ( A xe +oo )  = 
-e -oo  <->  ( A xe +oo )  = -oo ) )
1913, 18mpbid 210 1  |-  ( ( A  e.  RR*  /\  A  <  0 )  ->  ( A xe +oo )  = -oo )
Colors of variables: wff setvar class
Syntax hints:    -> wi 4    <-> wb 184    /\ wa 369    = wceq 1369    e. wcel 1756   class class class wbr 4304  (class class class)co 6103   0cc0 9294   +oocpnf 9427   -oocmnf 9428   RR*cxr 9429    < clt 9430    -ecxne 11098   xecxmu 11100
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 4425  ax-nul 4433  ax-pow 4482  ax-pr 4543  ax-un 6384  ax-cnex 9350  ax-resscn 9351  ax-1cn 9352  ax-icn 9353  ax-addcl 9354  ax-addrcl 9355  ax-mulcl 9356  ax-mulrcl 9357  ax-mulcom 9358  ax-addass 9359  ax-mulass 9360  ax-distr 9361  ax-i2m1 9362  ax-1ne0 9363  ax-1rid 9364  ax-rnegex 9365  ax-rrecex 9366  ax-cnre 9367  ax-pre-lttri 9368  ax-pre-lttrn 9369  ax-pre-ltadd 9370
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 2577  df-ne 2620  df-nel 2621  df-ral 2732  df-rex 2733  df-reu 2734  df-rab 2736  df-v 2986  df-sbc 3199  df-csb 3301  df-dif 3343  df-un 3345  df-in 3347  df-ss 3354  df-nul 3650  df-if 3804  df-pw 3874  df-sn 3890  df-pr 3892  df-op 3896  df-uni 4104  df-iun 4185  df-br 4305  df-opab 4363  df-mpt 4364  df-id 4648  df-po 4653  df-so 4654  df-xp 4858  df-rel 4859  df-cnv 4860  df-co 4861  df-dm 4862  df-rn 4863  df-res 4864  df-ima 4865  df-iota 5393  df-fun 5432  df-fn 5433  df-f 5434  df-f1 5435  df-fo 5436  df-f1o 5437  df-fv 5438  df-riota 6064  df-ov 6106  df-oprab 6107  df-mpt2 6108  df-1st 6589  df-2nd 6590  df-er 7113  df-en 7323  df-dom 7324  df-sdom 7325  df-pnf 9432  df-mnf 9433  df-xr 9434  df-ltxr 9435  df-le 9436  df-sub 9609  df-neg 9610  df-xneg 11101  df-xmul 11103
This theorem is referenced by:  xlemul1a  11263
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