Re: InverseFunction returning working function or just a symbol

*To*: mathgroup at smc.vnet.net*Subject*: [mg126574] Re: InverseFunction returning working function or just a symbol*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Sat, 19 May 2012 05:49:22 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

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=E1szl=F3 S=E1ndor 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 so metimes 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 murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305