#1485 limit bugs

closed
5
2008-08-31
2008-08-31
No

ex and ex1 are equivalent (replace 2^(2*N) with 4^N).

(%i1) ex:(%pi*N^(2*N+1)*2^(2*N))/((2*N-1)^(2*N)*(2*%e*N+%e));
(%o1) (%pi*N^(2*N+1)*2^(2*N))/((2*N-1)^(2*N)*(2*%e*N+%e))
(%i2) ex1:(%pi*N^(2*N+1)*4^N)/((2*N-1)^(2*N)*(2*%e*N+%e));
(%o2) (%pi*N^(2*N+1)*4^N)/((2*N-1)^(2*N)*(2*%e*N+%e))
(%i3) limit(ex, N, inf);
(%o3) 0
(%i4) limit(ex*%e, N, inf);
(%o4) inf
(%i5) limit(ex1, N, inf);
(%o5) %pi/2
(%i6) limit(ex1/%e, N, inf);
(%o6) 0
(%i7) limit(ex1*%e, N, inf);
(%o7) inf

The only correct answer is %o5. tlimit is correct for all examples.

Andrej

Discussion

  • Dan Gildea

    Dan Gildea - 2008-08-31
    • status: open --> closed
    • assigned_to: nobody --> dgildea
     
  • Dan Gildea

    Dan Gildea - 2008-08-31

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    Originator: NO

    Fixed in limit.lisp rev 1.55.

    (%i11) ex:(%pi*N^(2*N+1)*2^(2*N))/((2*N-1)^(2*N)*(2*%e*N+%e));
    (%o11) %pi*N^(2*N+1)*2^(2*N)/((2*N-1)^(2*N)*(2*%e*N+%e))
    (%i12) ex1:(%pi*N^(2*N+1)*4^N)/((2*N-1)^(2*N)*(2*%e*N+%e));
    (%o12) %pi*N^(2*N+1)*4^N/((2*N-1)^(2*N)*(2*%e*N+%e))
    (%i13) limit(ex, N, inf);
    (%o13) %pi/2
    (%i14) limit(ex*%e, N, inf);
    (%o14) %e*%pi/2
    (%i15) limit(ex1, N, inf);
    (%o15) %pi/2
    (%i16) limit(ex1/%e, N, inf);
    (%o16) %e^-1*%pi/2
    (%i17) limit(ex1*%e, N, inf);
    (%o17) %e*%pi/2

     

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