Re: PolynomialQ (wrong) behavior ?

*To*: mathgroup at smc.vnet.net*Subject*: [mg19238] Re: [mg19199] PolynomialQ (wrong) behavior ?*From*: "Andrzej Kozlowski" <andrzej at tuins.ac.jp>*Date*: Wed, 11 Aug 1999 02:06:51 -0400*Sender*: owner-wri-mathgroup at wolfram.com

In the message below I should have written (of course) "The expression 2x+1 is considered as a constant polynomial in y ..." -- Andrzej Kozlowski Toyama International University JAPAN http://sigma.tuins.ac.jp http://eri2.tuins.ac.jp ---------- >From: "Andrzej Kozlowski" <andrzej at tuins.ac.jp> To: mathgroup at smc.vnet.net >To: Drago Ganic <drago.ganic at in2.hr> , mathgroup at smc.vnet.net >Subject: [mg19238] Re: [mg19199] PolynomialQ (wrong) behavior ? >Date: Tue, Aug 10, 1999, 3:25 PM > > The function PolynomialQ is pretty simple minded. The expression 2x+1 is > considered as a constant polynomial in x. A little more controversially, it > is also considered as a constant polynomial in Sin[x], since it does not > explicitely involve Sin[x] as variable. This is quite consistent with the > behaviour of the derivative: > > In[1]:= > D[2x + 1, y] > Out[1]= > 0 > > In[2]:= > D[2x + 1, Sin[x]] > Out[2]= > 0 > > > -- > Andrzej Kozlowski > Toyama International University > JAPAN > http://sigma.tuins.ac.jp > http://eri2.tuins.ac.jp > > > ---------- >>From: "Drago Ganic" <drago.ganic at in2.hr> To: mathgroup at smc.vnet.net >>To: mathgroup at smc.vnet.net >>Subject: [mg19238] [mg19199] PolynomialQ (wrong) behavior ? >>Date: Tue, Aug 10, 1999, 8:52 AM >> > >> Hi, >> >> f = 2x +1 >> >> PolynomialQ [ f, x ] >> True >> >> That's OK. But why the following >> >> PolynomialQ [ f, y ] >> True >> >> PolynomialQ [ f, Sin[x] ] >> True >> >> Greetings, >> Drago Ganic >> >> >> >> >> >> >>