#2216 indefinite integration, wrong result.

closed
nobody
5
2011-06-29
2011-06-26
Ilya Dikarev
No

maxima tells a wrong result for a
integrate(coth(x),x);

(%i54) integrate(coth(x),x);
(%o54) log(sinh(x))

The right result is log(abs(sinh(x)))

Discussion

  • Ilya Dikarev
    Ilya Dikarev
    2011-06-26

    Oh. The Problem is in the integrate(1/x,x); The maxima tells it's log(x), but the right result is log(abs(x));

     
  • Ilya Dikarev
    Ilya Dikarev
    2011-06-27

    • status: open --> wont-fix
     
  • Barton Willis
    Barton Willis
    2011-06-29

    integrate(1/x,x) = log(abs(x)) is ok on the real line, but invalid in
    the complex plane. Same for integrate(coth(x),x) = log(abs(sinh(x))).

    There is an option variable logabs that partially controls this.

     
  • Barton Willis
    Barton Willis
    2011-06-29

    • status: wont-fix --> closed