MathGroup Archive 1995

[Date Index] [Thread Index] [Author Index]

Search the Archive

derivatives of indexed variables


What am I missing?

total derivative of unspecified y:

In[1]:= Dt[y,x]

Out[1]= Dt[y, x]

But if we take the derivaitve of an undefined indexed variable
it is assumed to be a constant..

In[2]:= Dt[a[1],x]

Out[2]= 0

note however that the indexed symbol could easily represent a non-constant.

In[3]:= a[1]=y; Dt[a[1],x]

Out[3]= Dt[y, x]


clearly the trouble is that there is no distinction between an indexed
symbol and a function evaluated at a fixed point..
Is there a workaround?










  • Prev by Date: Point Labels on XY plot
  • Next by Date: WTB Mathematica 2.2x Proffessional for MAC
  • Previous by thread: Re: derivatives of indexed variables
  • Next by thread: derivatives of indexed variables