#203 trigsimp fails in simplest case

closed
nobody
Lisp Core (471)
5
2005-05-13
2002-12-27
No

In Maxima 5.5 GCL Windows.

trigsimp(sin(x)^2+cos(x)^2) fails to simplify, even though
the online doc explicitly says it "employs the identities
sin(x)^2 + cos(x)^2 = 1".

True, it also says "...so that further simplification may
be obtained by using TRIGREDUCE on the result".

I suggest removing the reference to the s2+c2=1
identity, and instead saying:

"normally TrigSimp should be followed by TrigReduce
and RatSimp or RadCan for full simplification"

I also think that something called TrigSimp should be
able to handle this case.... Perhaps its name should be
changed if it's less ambitious than a general
trigonometric simplifier....

Discussion

  • Robert Dodier

    Robert Dodier - 2005-05-05
    • labels: --> Lisp Core
     
  • Robert Dodier

    Robert Dodier - 2005-05-05

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    Appears to have been fixed somewhere along the way: CVS
    Maxima on clisp, 5.9.1 official release on cmucl, and CVS on
    gcl (all linux) all yield 1 for trigsimp(sin(x)^2+cos(x)^2) .

    Leaving this report open pending verification on Windows.

     
  • Barton Willis

    Barton Willis - 2005-05-06

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    On windows XP

    (%i1) trigsimp(sin(x)^2+cos(x)^2);
    (%o1) 1
    (%i2) build_info();
    Maxima version: 5.9.1
    Maxima build date: 7:34 9/24/2004
    host type: i686-pc-mingw32
    lisp-implementation-type: Kyoto Common Lisp
    lisp-implementation-version: GCL 2.6.5
    (%o2)

    I think this bug can be closed (but my GCL is a bit old).

    Barton

     
  • Robert Dodier

    Robert Dodier - 2005-05-13
    • status: open --> closed
     
  • Robert Dodier

    Robert Dodier - 2005-05-13

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    user_id=501686

    Closing this bug as current behavior on Windows/gcl,
    linux/gcl, linux/cmucl, and linux/clisp yields the expected
    result.

     

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