Bart.Vandewoestyne at telenet.be
Tue Apr 8 10:54:09 CDT 2008
On Tue, Apr 08, 2008 at 01:24:44PM +0100, Jaime Villate wrote:
> On Mon, 2008-04-07 at 23:28 +0200, Bart Vandewoestyne wrote:
> > I would like to do this using Maxima. The integral I need to
> > calculate is
> > (%i8) integrate(abs(2*x*sin(x)-cos(1/x)), x, 0, 2/%pi);
> (%i9) quad_qags(abs(2*x*sin(x)-cos(1/x)), x, 0, 2/%pi);
> ***MESSAGE FROM ROUTINE DQAGS IN LIBRARY SLATEC.
> ***INFORMATIVE MESSAGE, PROG CONTINUES, TRACEBACK REQUESTED
> * ABNORMAL RETURN
> * ERROR NUMBER = 1
> ***END OF MESSAGE
> (%o9) [.5254584214118198, 2.7506663065146597e-4, 8379, 1]
> I don't know if the returned value (.525...) is correct. The error code
> 1 means it had to take too many sub-intervals. Look at "? quad_qags"
I also tried this... but I don't trust this result... two people
on comp.soft-sys.math.maple reported a value of 0.6053..., each
obtained his result independently from the other... so i think
that is probably more correct.
They obtained it by integrating between the zeros of the function
and summing the results.
I'm trying to understand their strategy and convert it to Maxima, but I haven't
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