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RE: Integrate (deutsch)

  • To: MathGroup at yoda.physics.unc.edu
  • Subject: RE: Integrate (deutsch)
  • From: reiszig at e-technik.tu-dresden.dbp.de
  • Date: Mon, 8 Mar 1993 16:47:49 +0100

------------------------------ Start of body part 1

Hallo,
Mr. Deutsch had a problem concerning Integrate (see below).
The reason for Simplify not to change the form of Out[1] into
1/4 (x + c)^4 is that Out[1] is different from that. 
Try 
Integrate[ (xx + c)^3,{xx,-c,x}], maybe a Factor is needed thereafter.
G. Reiszig, Dresden, 8 Mar 93

Mr. Deutsch's mail:

------------------------------ Start of body part 2

                             - OSITEL/400 message -

SubmissionTime:    04/03/93-22:00:57
DeliveryTime:      06/03/93-09:20:55
Originator:        C=de;A=dbp;P=edu;O=bu;OU=bu-pub;S=deutsch
PrimaryRecipients: C=de;A=dbp;P=edu;O=unc;OU=physics;OU=yoda;S=mathgroup
Subject:           Integrate
Importance:        normal

Hello Mathgroup,
 
 
       I have a question which I suspect has been discussed before.
 
Is there a reason why Integrate[ (x + c)^3, x ] does not return 
 
               (x + c)^4
               ---------
                   4
 
Instead here is the result:
 
 
Mathematica 2.0 for SPARC
Copyright 1988-91 Wolfram Research, Inc.
 -- X11 windows graphics initialized -- 
 
In[1]:= Integrate[ (x + c)^3, x ]
 
                  2  2           4
         3     3 c  x       3   x
Out[1]= c  x + ------- + c x  + --
                  2             4
 
In[2]:= Simplify[%]
 
                  2  2           4
         3     3 c  x       3   x
Out[2]= c  x + ------- + c x  + --
                  2             4
 
In[3]:= D[%,x]
 
         3      2          2    3
Out[3]= c  + 3 c  x + 3 c x  + x
 
 
In[4]:= Simplify[%]
 
               3
Out[4]= (c + x)
 
 
Clearly, the output Out[1] is correct but
is there some way to force Out[1] to look like:
 
               (x + c)^4
               ---------
                   4
 
Simplify, doesn't seem to do the job either.
 
 
David Deutsch
Information Technology
Boston University
deutsch at it.bu.edu
 




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