Re: InverseFunction returning working function or just a symbol

*To*: mathgroup at smc.vnet.net*Subject*: [mg126566] Re: InverseFunction returning working function or just a symbol*From*: LÃszlÃ SÃndor <sandorl at gmail.com>*Date*: Sat, 19 May 2012 05:46:36 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <201205180923.FAA17055@smc.vnet.net> <4FB652E4.8010608@math.umass.edu>

Hi, Sorry about this, I learnt this, but after I posted here already. I posted the question on mathematica.SE too, with no confusing tags: http://mathematica.stackexchange.com/questions/5691/inverse-function-not-working-but-providing-values-for-some-arguments-a-symbo Thanks, Laszlo On Fri, May 18, 2012 at 9:47 AM, Murray Eisenberg <murray at math.umass.edu> wrote: > Please don't include all the In[...] and Out[...] labels, because they make > it hard to copy and paste executable code into Mathematica. > > On 5/18/12 5:23 AM, L=C3=A1szl=C3=B3 S=C3=A1ndor wrote: >> >> Hi all, >> I am puzzled by the following behavior (focus on the end, the rest is only >> to provide context): >> >> In[88]:= u[c_,l_]:=Log[c]-Log[1+l^(1+k)/(1+k)] >> In[14]:= T[z_]:=(1-0.84/1.3) * z >> In[103]:= umaxType[n_]:=MaxValue[{u[n l-T[n l],l],l>=0},l] >> In[101]:= lType[n_]:=ArgMax[{u[n l-T[n l],l],l>=0},l] >> In[105]:= zType[n_] := n lType[n] >> In[111]:= Type := InverseFunction[zType] >> In[134]:= Type[5345] >> Out[134]= 5030.99 >> In[136]:= Type[2] >> Out[136]= (zType^(-1))[2] >> In[137]:= Type[4324424] >> Out[137]= (zType^(-1))[4324424] >> >> I understand that there could be many justified reasons why the inversion >> might not work for a specific argument. Still, I am deeply puzzled that >> sometimes I receive back a symbol that nothing else is able to do anything >> about (why not an error message, then?), sometimes a number. How could this >> be improved? >> >> Thanks! >> > > -- > Murray Eisenberg =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 = =C2 =C2 murray at math.umass.edu > Mathematics & Statistics Dept. > Lederle Graduate Research Tower =C2 =C2 =C2 phone 413 549-1020 (H= ) > University of Massachusetts =C2 =C2 =C2 =C2 =C2 =C2 =C2= =C2 413 545-2859 (W) > 710 North Pleasant Street =C2 =C2 =C2 =C2 =C2 =C2 fax = =C2 413 545-1801 > Amherst, MA 01003-9305 >

**References**:**InverseFunction returning working function or just a symbol***From:*László Sándor <sandorl@gmail.com>