used signed dummy when computing leading_term in limit
used signed dummy when computing leading_term in limit

    This allows powers like sqrt(1/x) to simplify to 1/sqrt(x) and
    be detected as x-based powers.

jerli/sympy,shipci/sympy,srjoglekar246/sympy,iamutkarshtiwari/sympy,abhiii5459/sympy,MridulS/sympy,asm666/sympy,Shaswat27/sympy,wyom/sympy,abloomston/sympy,bukzor/sympy,postvakje/sympy,Vishluck/sympy,moble/sympy,moble/sympy,ga7g08/sympy,drufat/sympy,Curious72/sympy,kumarkrishna/sympy,emon10005/sympy,dqnykamp/sympy,sunny94/temp,asm666/sympy,sahilshekhawat/sympy,Arafatk/sympy,Davidjohnwilson/sympy,lindsayad/sympy,aktech/sympy,toolforger/sympy,aktech/sympy,oliverlee/sympy,kevalds51/sympy,Gadal/sympy,Arafatk/sympy,sahmed95/sympy,hargup/sympy,AkademieOlympia/sympy,abhiii5459/sympy,dqnykamp/sympy,bukzor/sympy,Davidjohnwilson/sympy,Sumith1896/sympy,aktech/sympy,farhaanbukhsh/sympy,wyom/sympy,sunny94/temp,maniteja123/sympy,drufat/sympy,saurabhjn76/sympy,toolforger/sympy,grevutiu-gabriel/sympy,ahhda/sympy,Sumith1896/sympy,wyom/sympy,madan96/sympy,Titan-C/sympy,MechCoder/sympy,skidzo/sympy,kaichogami/sympy,abhiii5459/sympy,vipulroxx/sympy,jbbskinny/sympy,Shaswat27/sympy,cswiercz/sympy,diofant/diofant,rahuldan/sympy,sahilshekhawat/sympy,Curious72/sympy,postvakje/sympy,jbbskinny/sympy,kumarkrishna/sympy,maniteja123/sympy,lidavidm/sympy,abloomston/sympy,kumarkrishna/sympy,sahilshekhawat/sympy,asm666/sympy,abloomston/sympy,jbbskinny/sympy,atreyv/sympy,ahhda/sympy,saurabhjn76/sympy,maniteja123/sympy,sampadsaha5/sympy,mafiya69/sympy,AunShiLord/sympy,pbrady/sympy,Curious72/sympy,mcdaniel67/sympy,mcdaniel67/sympy,lidavidm/sympy,meghana1995/sympy,shikil/sympy,vipulroxx/sympy,Mitchkoens/sympy,kevalds51/sympy,kevalds51/sympy,hrashk/sympy,VaibhavAgarwalVA/sympy,liangjiaxing/sympy,liangjiaxing/sympy,ga7g08/sympy,wanglongqi/sympy,hargup/sympy,toolforger/sympy,rahuldan/sympy,MechCoder/sympy,kaushik94/sympy,debugger22/sympy,ahhda/sympy,madan96/sympy,mafiya69/sympy,yashsharan/sympy,kaichogami/sympy,kaichogami/sympy,MridulS/sympy,jerli/sympy,amitjamadagni/sympy,beni55/sympy,jamesblunt/sympy,sampadsaha5/sympy,souravsingh/sympy,AkademieOlympia/sympy,yukoba/sympy,Gadal/sympy,atreyv/sympy,emon10005/sympy,atsao72/sympy,ga7g08/sympy,vipulroxx/sympy,lindsayad/sympy,VaibhavAgarwalVA/sympy,Sumith1896/sympy,ChristinaZografou/sympy,yukoba/sympy,pandeyadarsh/sympy,kaushik94/sympy,ChristinaZografou/sympy,chaffra/sympy,atsao72/sympy,atreyv/sympy,Mitchkoens/sympy,emon10005/sympy,AunShiLord/sympy,shipci/sympy,Arafatk/sympy,meghana1995/sympy,kmacinnis/sympy,bukzor/sympy,pbrady/sympy,Designist/sympy,debugger22/sympy,yukoba/sympy,Gadal/sympy,rahuldan/sympy,mcdaniel67/sympy,Designist/sympy,skidzo/sympy,Mitchkoens/sympy,pbrady/sympy,sunny94/temp,hrashk/sympy,Vishluck/sympy,chaffra/sympy,Titan-C/sympy,mafiya69/sympy,pandeyadarsh/sympy,cccfran/sympy,shikil/sympy,yashsharan/sympy,postvakje/sympy,liangjiaxing/sympy,atsao72/sympy,shipci/sympy,beni55/sympy,garvitr/sympy,oliverlee/sympy,debugger22/sympy,sampadsaha5/sympy,sahmed95/sympy,Davidjohnwilson/sympy,jamesblunt/sympy,wanglongqi/sympy,beni55/sympy,kmacinnis/sympy,amitjamadagni/sympy,madan96/sympy,lidavidm/sympy,drufat/sympy,MridulS/sympy,dqnykamp/sympy,VaibhavAgarwalVA/sympy,jamesblunt/sympy,MechCoder/sympy,saurabhjn76/sympy,iamutkarshtiwari/sympy,garvitr/sympy,sahmed95/sympy,jaimahajan1997/sympy,skidzo/sympy,iamutkarshtiwari/sympy,Shaswat27/sympy,oliverlee/sympy,lindsayad/sympy,kmacinnis/sympy,pandeyadarsh/sympy,AunShiLord/sympy,flacjacket/sympy,meghana1995/sympy,ChristinaZografou/sympy,skirpichev/omg,grevutiu-gabriel/sympy,Titan-C/sympy,cccfran/sympy,wanglongqi/sympy,shikil/sympy,yashsharan/sympy,kaushik94/sympy,chaffra/sympy,AkademieOlympia/sympy,cswiercz/sympy,Vishluck/sympy,farhaanbukhsh/sympy,Designist/sympy,cswiercz/sympy,jaimahajan1997/sympy,souravsingh/sympy,grevutiu-gabriel/sympy,garvitr/sympy,souravsingh/sympy,cccfran/sympy,moble/sympy,hargup/sympy,hrashk/sympy,jerli/sympy,jaimahajan1997/sympy,farhaanbukhsh/sympy