RE: Bug in math4
- To: mathgroup at smc.vnet.net
- Subject: [mg20662] RE: [mg20633] Bug in math4
- From: "Ersek, Ted R" <ErsekTR at navair.navy.mil>
- Date: Sun, 7 Nov 1999 02:10:01 -0500
- Sender: owner-wri-mathgroup at wolfram.com
Lennart Bengtsson indicated the problem discussed earlier might be at
x=Pi/2. Below we see this is the case. I don't know I didn't make the
connection between 1.57... and Pi/2 earlier.
In[1]:=
Integrate[Sqrt[2-Sin[x]],{x,1,4}]
Out[1]= (*** Wrong answer ***)
-2*EllipticE[(-4 + Pi/2)/2, -2] +
2*EllipticE[(-1 + Pi/2)/2, -2] +
4*EllipticF[I*ArcSinh[1/Sqrt[2]], -2]
In[2]:=
Integrate[Sqrt[2-Sin[x]],{x,1,Pi/2,4}]
Out[2]= (*** Right answer ***)
-2*EllipticE[(-4 + Pi/2)/2, -2] +
2*EllipticE[(-1 + Pi/2)/2, -2]
--------------------
Regards,
Ted Ersek
For Mathematica tips, tricks see
http://www.dot.net.au/~elisha/ersek/Tricks.html