Services & ResourcesWolfram ForumsMathGroup Archive

[Date Index] [Thread Index] [Author Index]

Strange result for a definite integral: Unknown Symbol (\.10) returned

• To: mathgroup at smc.vnet.net
• Subject: [mg81825] Strange result for a definite integral: Unknown Symbol (\.10) returned
• From: "W. Craig Carter" <ccarter at mit.edu>
• Date: Thu, 4 Oct 2007 04:26:18 -0400 (EDT)

Hello, I am getting a result that I can't understand. An unknown symbol
"\.10" is appearing.

InputForm[integrand] is
(R*(R - x*Cos[t] - y*Sin[t]))/(3*(R^2 + x^2 + y^2 + (z - zeta)^2 - 2*R*(x*Cos[t] + y*Sin[t]))^3)

InputForm{assumptions] is
{R > 0, L > 0, Element[zeta, Reals], Element[x, Reals], Element[y, Reals], Element[z, Reals]}

integral = Integrate[integrand,{t,0,2 Pi}, Assumptions->assumptions]

returns (after a longish evaluation, about 20 minutes on my  machine)
InputForm[integral] is
(2*\.10*R^2*(R^4 - 2*x^4 - 2*y^4 - y^2*z^2 + z^4 - 
x^2*(4*y^2 + (z - zeta)^2) + R^2*(x^2 + y^2 + 2*(z - 
zeta)^2) +
    2*y^2*z*zeta - 4*z^3*zeta - y^2*zeta^2 + 6*z^2*zeta^2 - 
4*z*zeta^3 + zeta^4)*
   (Log[(-2*(R^2 + 2*R*x + x^2 + y^2 + z^2 - 2*z*zeta + 
zeta^2))/Sqrt[-R^4 + 2*R^2*(x^2 + y^2 - (z - zeta)^2) -
        (x^2 + y^2 + (z - zeta)^2)^2]] - Log[(2*(R^2 + 2*R*x 
+ x^2 + y^2 + z^2 - 2*z*zeta + zeta^2))/
      Sqrt[-R^4 + 2*R^2*(x^2 + y^2 - (z - zeta)^2) - (x^2 + 
y^2 + (z - zeta)^2)^2]]))/
  (3*(-R^4 + 2*R^2*(x^2 + y^2 - (z - zeta)^2) - (x^2 + y^2 + 
(z - zeta)^2)^2)^(5/2))

(The \.10 appears as a little space, subsequent 
operations give me a tiny little space to a power)


FullForm[integral] returns
Times[Rational[2, 3], \.10, ....

What is the symbol \.10 doing in there? What is it?

I am using the 64-bit kernel on a macintosh intel chip dual core machine. Math 6.01

Thanks, Craig

• Follow-Ups:
  • Re: Strange result for a definite integral: Unknown Symbol
    • From: "W. Craig Carter" <ccarter@mit.edu>