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MathGroup Archive 1996

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Re: implicit differentiation

  • To: mathgroup at smc.vnet.net
  • Subject: [mg2883] Re: [mg2858] implicit differentiation
  • From: Lou Talman <me at talmanl.mscd.edu>
  • Date: Thu, 4 Jan 1996 03:05:29 -0500

An alternative to Dave Wagner's use of Dt to implement  
implicit differentiation is to make the dependence explicit:

In[1]:=
  imp[u_, v_] := Log[v] + u v - 1

In[2]:=
  Map[D[#, x]&, imp[x, y[x]] == 0]

Out[2]=

                   y'[x]
  y[x] + x y'[x] + ----- == 0
                   y[x]

In[3]:=
  Solve[%, y'[x]]

Out[3]=

                     2
                 y[x]
  {{y'[x] -> -(----------)}}
               1 + x y[x]

--Lou Talman

-------------------------------
Begin forwarded message:

>From: marshall at CIS.Edu.HK
>Subject: [mg2858] implicit differentiation

How can I do implicit differentiation ?



==== [MESSAGE SEPARATOR] ====


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