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Re: [mg5119] Integration..Constants
Posted:
Nov 7, 1996 12:44 AM


On Wed, 30 Oct 1996, Dennis Michael Winters wrote:
> I have tried several times to perform an integration(math..2.2.3)B > similar to the following. > > In[1]:=Integrate[(ao+x)^1 (bo^2), x] > > The results, however, are always incorrect: > > Out[1]=ln(ao+x) <where the constant "ao" should be positive. > > ... more stuff
Dennis,
It seems to me that you made a typo in your question. Specifically, if you give Mma the integral
In[1]:=Integrate[(aox)^1, x]
then you probably get (I haven't checked this on Mma myself)
Out[1]:=ln[ao+x]
But, try taking a derivative of this, you get the expected answer. You might have expected to get
Out[1]:= ln[aox]
and, naturally enough, if you take a derivative of this, you get the expected answer. So, what's going on? Well, these two answers differ by a constant:
ln[ao+x] = ln[ (1) (aox) ] = ln[1]  ln[aox]
and
ln[1] = ln[ Exp[I Pi] ] =  I Pi
Thus, Mma is not doing anything wrong here.
Carl Physics Dept U of Washington
carlw@u.washington.edu



