Strange result with Integrate
- To: mathgroup at smc.vnet.net
- Subject: [mg38242] Strange result with Integrate
- From: Ray <rayfg at optonline.net>
- Date: Tue, 10 Dec 2002 04:09:40 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
Can anyone explain the following results?
In[8]:=
r[t_]:=4-3Sin[t]
In[9]:=
\!\(NIntegrate[Sqrt[r[t]\^2 + \(r'\)[t]\^2], {t, 0, 2 \[Pi]}]\)
Out[9]=
28.8142
In[10]:=
\!\(Integrate[Sqrt[r[t]\^2 + \(r'\)[t]\^2], {t, 0, 2 \[Pi]}] // N\)
Out[10]=
-18.9606
The result with Integrate //N is -18.9606 but with NIntegrate it is
28.8142. Thanks.
Ray Gittings