#400 Taylor Illegal log kernel: log(cos(th)) @ %pi/2

closed
nobody
5
2007-12-26
2003-09-16
No

taylor(log(cos(th)),th,%pi/2,2)
gives the internal error Illegal log kernel

but taylor(log(-sin(th)),th,0,2), which is equivalent,
gives a perfectly reasonable result.

Discussion

  • Stavros Macrakis

    • summary: Illegal log kernel: log(cos(th)) @ %pi/2 --> Taylor Illegal log kernel: log(cos(th)) @ %pi/2
     
  • Robert Dodier

    Robert Dodier - 2006-04-09
    • labels: --> Lisp Core - Taylor
     
  • Dan Gildea

    Dan Gildea - 2007-12-26

    Logged In: YES
    user_id=1797506
    Originator: NO

    Fixed in hayat.lisp rev 1.31...

    (%i7) taylor(log(cos(th)),th,%pi/2,2);
    (%o7) log((2*th-%pi)/2)+log(-1)-(th-%pi/2)^2/6

    ... though still not all cases are handled ....

    (%i8) taylor(log(log(cos(th))),th,%pi/2,2);
    Maxima encountered a Lisp error:
    Unhandled kernel in tvar-lim

     
  • Dan Gildea

    Dan Gildea - 2007-12-26
    • status: open --> closed
     

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