Re: BesselK
- To: mathgroup at smc.vnet.net
- Subject: [mg15634] Re: BesselK
- From: Stephen P Luttrell <luttrell at signal.dra.hmg.gb>
- Date: Sat, 30 Jan 1999 04:28:33 -0500 (EST)
- Organization: Defence Evaluation and Research Agency
- References: <78pcrt$d4r@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
>i tried to integrate BesselK[0,x]/x on mathematica and eventually it
>gives a zero.
>
>Integrate[BesselK[0,x]/x,x] = 0
>
>can someone please explain.
This integral is divergent. Here is what Mathematica 3 does with it:
In[1]:=Integrate[BesselK[0,x]/x,x]
\!\(Power::"infy" \( : \ \) "Infinite expression \!\(1\/0\)
encountered."\)
\!\(Power::"infy" \( : \ \) "Infinite expression \!\(1\/0\)
encountered."\)
\[Infinity]::"indet":
"Indeterminate expression
\!\(\*InterpretationBox[\"ComplexInfinity\", \ DirectedInfinity[]] +
\*InterpretationBox[\"ComplexInfinity\", \ DirectedInfinity[]]\)
encountered."
Out[7]=0
Did you mean to do this:
In[5]:=Integrate[x BesselK[0,x],x]
Out[5]=-x BesselK[1,x]
Stephen P Luttrell
Signal Processing and Imagery Department DERA Malvern, St.Andrew's Road
Malvern, United Kingdom, WR14 3PS
+44 (0)1684 894046 (tel)
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luttrell at signal.dera.gov.uk (email)
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