
Re: Query regarding Function
Posted:
Mar 13, 2013 4:18 AM


[This thread is now closed. There have been enough answers.  Moderator]
On 12/03/2013 04:34, Rahul Chakraborty wrote: > Dear all, > > Case1: In the following code > > Clear[f,x,y] > g=Function[{x,y},x^2+2xy][b,a] > > The output is found to be b^2+2 xy > > Case2: But for the code > > Clear[f,x,y] > g=Function[{x,y},x^2+2y][b,a] > > The output is 2 a+b^2 > > Hence my query is why in case 1 x*y is not replaced by b and a whereas in case 2 it got replaced ? > > Regards, > rc > Variable names in Mathemnatica can be more than one character long  remember that computer algebra can require a lot of variables! Thus xy is a quite distinct variable  space the two characters out to get a product: x y .
Note that it is always useful to examine dubious expressions using FullForm (possibly with Hold to prevent evaluation) to determine their true structure. This resolved a host of puzzles:
In[1]:= x y //FullForm Out[1]//FullForm= Times[x,y]
In[2]:= xy //FullForm Out[2]//FullForm= xy
In[3]:= x*y //FullForm Out[3]//FullForm= Times[x,y]
David Bailey http://www.dbaileyconsultancy.co.uk

