wmi2

WebMathematics Interactive 2 bug tracking system.
Tasklist

FS#159 - Taylor series for ctg x gives a bad answer

Attached to Project: wmi2
Opened by Kovacs Zoltan (kovzol) - Thursday, 22 November 2007, 11:44 GMT+2
Last edited by Kovacs Zoltan (kovzol) - Saturday, 03 April 2010, 12:18 GMT+2
Task Type Bug Report
Category Backend / Core
Status Closed
Assigned To Kovacs Zoltan (kovzol)
Fekete Arpad (arpad)
Kornel Csernai (csko)
Operating System All
Severity Medium
Priority Normal
Reported Version Development
Due in Version 2.2
Due Date Undecided
Percent Complete 100%
Votes 0
Private No

Details

This may be a Maxima bug, I don't know exactly.

ctg x does not have a Taylor(-MacLaurin) series but a Laurent series only due to its singularity in 0. We should check if we use the Taylor expansion from Maxima or this is a general function which also gives the Laurent expansion, too.

Another suggestion is to add another maxima button to provide general Taylor series expansions, not only for the point 0 but other ones, too. My concrete idea is to create another icon (using the log(x) expansion for the point 1) which has 3 parameters: the function, the point and the number of the elements in the expansion.
This task depends upon

Closed by  Kovacs Zoltan (kovzol)
Saturday, 03 April 2010, 12:18 GMT+2
Reason for closing:  Fixed
Comment by Fekete Arpad (arpad) - Tuesday, 11 December 2007, 11:54 GMT+2
There is a taylorp(expr) function in maxima which helps us decide if expr is a Taylor series or not.
And there is also a taylorinfo(expr) function.
But the taylor function really gives Taylor or Laurent series.
http://maxima.sourceforge.net/docs/manual/en/maxima_30.html#SEC122
Comment by Fekete Arpad (arpad) - Tuesday, 11 December 2007, 12:11 GMT+2
Unfortunately, the taylorp(expr) returns true if
expr = taylor(input,x,0,10)
I don't know how to distunguish between the Taylor and Laurent series.

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