#777 limit(atan(x)/(1/exp(1)-exp(-(1+x)^2)),x,inf,plus) - wrong

closed
nobody
None
5
2005-10-06
2005-09-04
No

(%i1) limit(atan(x)/(1/exp(1)-exp(-(1+x)^2)),x,inf,plus);
%e %i log(- 1)
(%o1) --------------
2
Correct result is %e*%pi/2

Discussion

  • Raymond Toy
    Raymond Toy
    2005-09-14

    Logged In: YES
    user_id=28849

    I think this is very likely caused by the fact that maxima
    thinks

    limit(log((1-%i*x)/(1+%i*x)),x,inf,plus)

    is log(-1) = %i*%pi/2. The correct answer is -%i*%pi/2,
    because argument of the log is always in the third quadrant
    (x < 0, y < 0).

    I think it's because maxima thinks limit log(x) = log(limit
    x) in this case since the limit of the arg is a finite number.

     
  • Raymond Toy
    Raymond Toy
    2005-10-06

    • status: open --> closed