Mathematica 9 is now available
Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2009

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

Search the Archive

Re: Correction to "Fundamental Theorem of Calculus and Mathematica"

  • To: mathgroup at smc.vnet.net
  • Subject: [mg100767] Re: [mg100727] Correction to "Fundamental Theorem of Calculus and Mathematica"
  • From: Curtis Osterhoudt <cfo at lanl.gov>
  • Date: Sat, 13 Jun 2009 06:04:10 -0400 (EDT)
  • Organization: LANL
  • References: <200906120144.VAA17857@smc.vnet.net>
  • Reply-to: cfo at lanl.gov

  Works here ("7.0 for Linux x86 (32-bit) (November 11, 2008)").

In[4]:= f[x_] := Integrate[Sin[t^2], {t, 0, x}]

In[5]:= D[f[x], x]

Out[5]= Sin[x^2]

In[6]:= g[x_] := Integrate[Exp[-t^2], {t, 0, x}]

In[7]:= D[g[x], x]

Out[7]= E^-x^2




On Thursday 11 June 2009 07:44:34 pm Len wrote:
> Greetings:
> 
> I define a function (using f[x_]:=) as the definite integral (from 0
> to x) of sin(t^2).  When I differentiate using Mathematica I get the
> correct answer of sin(x^2).
> 
> But when I define a function (using g[x_]:=) as the definite integral
> (from 0 to x) of e^(-t^2) and differentiate, I get the incorrect
> answer of 0.  (The correct answer is e^(-x^2).)
> 
> Why the inconsistency?
> 
> Oddly, if I define the function g above using "=" instead of ":=", all
> works well.
> 
> Can someone explain the odd behavior?
> 
> Thanks,
> 
> Len
> 
> 


-- 
==================================
Curtis Osterhoudt
cfo at remove_this.lanl.and_this.gov
PGP Key ID: 0x4DCA2A10
==================================


  • Prev by Date: Re: perturbation methods example from stephen lynch's book?
  • Next by Date: Re: Creating Matrix from vectors specific issue.
  • Previous by thread: Correction to "Fundamental Theorem of Calculus and Mathematica"
  • Next by thread: Re: Correction to "Fundamental Theorem of Calculus and