Re: asymptotics
- To: mathgroup at smc.vnet.net
- Subject: [mg76692] Re: asymptotics
- From: dimitris <dimmechan at yahoo.com>
- Date: Sat, 26 May 2007 04:22:00 -0400 (EDT)
- References: <f33qsc$mc6$1@smc.vnet.net>
Andrzej and Jens thanks a lot for assistance! Dimitris / dimitris : > Sorry fellas if I ask something trivial > but currently I can't find anything! > > In another CAS I took > > f:=asympt(exp(-y*sqrt(1+m^2*u^2)/m),u,5); > > / 2 1/2 2 2 1/2 2 2 > | y (m ) y y (m ) (-6 m + y ) > f := |1 - --------- + ------- - ---------------------- > | 3 4 2 7 3 > \ 2 m u 8 m u 48 m u > > 2 2 2 \ 2 1/2 > y (-24 m + y ) 1 | / y (m ) u > + ---------------- + O(----)| / exp(-----------) > 8 4 5 | / m > 384 m u u / > > ff:=simplify(convert(f,polynom)) assuming m>0; > ff := 1/384*exp(- > y*u)*(384*m^8*u^4-192*y*m^6*u^3+48*y^2*m^4*u^2+48*y*m^4*u-8*y^3*m^2*u-24*y^2*m^2+y^4)/ > m^8/u^4 > > In Mathematica I can't get the expansion in infinity > > In[113]:= Series[Exp[(-y)*(Sqrt[1 + m^2*u^2]/m)], {u, Infinity, 10}] > Out[113]= E^(-((Sqrt[1 + m^2*u^2]*y)/m)) > > What do I miss here? > > Thanks > Dimitris