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Groups > comp.soft-sys.math.mathematica > #2292
| From | Murray Eisenberg <murray@math.umass.edu> |
|---|---|
| Newsgroups | comp.soft-sys.math.mathematica |
| Subject | Re: Numerical/analytical integration around a pole |
| Date | 2011-05-11 08:28 +0000 |
| Organization | Steven M. Christensen and Associates, Inc and MathTensor, Inc. |
| Message-ID | <iqdhc2$1bl$1@smc.vnet.net> (permalink) |
With Mathematica 8.0.1 under Windows (32-bit), I get exactly the same
results from Integrate and NIntegrate here, even when I display 15
digits in the results from both.
On 5/10/2011 8:31 AM, A. Lapraitis wrote:
> Hello,
>
> I am trying to integrate a 1/(polynomial) function around its pole.
> Could someone explain, why Integrate and NIntegrate give different
> results?
>
> Thanks a lot in advance!
> A. L.
>
>
> In[83]:= y[x_] := .24583 + 0.0175121 x - 0.793943 x^2 + 0.534908 x^3 -
> 0.650198 x^4;
>
> (* Locating the pole *)
> In[86]:= FindRoot[y[x] == 0, {x, .6}]
> Out[86]= {x -> 0.601945}
>
> In[84]:= Integrate[1/(y[x] + I/1000), {x, .5, .7}]
> Out[84]= 5.25406 - 15.0137 I
>
> In[85]:= NIntegrate[1/(y[x] + I/1000), {x, .5, .7}]
> Out[85]= 0.323456 - 3.37701 I
>
--
Murray Eisenberg murray@math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower phone 413 549-1020 (H)
University of Massachusetts 413 545-2859 (W)
710 North Pleasant Street fax 413 545-1801
Amherst, MA 01003-9305
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Re: Numerical/analytical integration around a pole Murray Eisenberg <murray@math.umass.edu> - 2011-05-11 08:28 +0000
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