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#3189 -1/taylor(x,x,0,1) => 0

None
open
nobody
taylor (27)
5
2024-06-03
2016-07-20
No
1/taylor(x,x,0,1) => 1/x+...   OK
taylor(x,x,0,1)*taylor(1/x,x,0,1) => 1+... OK

-1/taylor(x,x,0,1) => 0+...   WRONG
2/taylor(x,x,0,1) => 0+...    WRONG
x/taylor(x,x,0,1) => 0+...    WRONG
taylor(x,x,0,1)/taylor(x,x,0,1) => 0+... WRONG

Discussion

  • Robert Dodier

    Robert Dodier - 2024-06-03
    • labels: --> taylor
     
  • Stavros Macrakis

    • Description has changed:

    Diff:

    --- old
    +++ new
    @@ -1,5 +1,5 @@
         1/taylor(x,x,0,1) => 1/x+...   OK
    -    taylor(x,x,0,1)*taylor(1/x,x,0,1) => 1/x+... OK
    +    taylor(x,x,0,1)*taylor(1/x,x,0,1) => 1+... OK
    
         -1/taylor(x,x,0,1) => 0+...   WRONG
         2/taylor(x,x,0,1) => 0+...    WRONG
    
     
  • Stavros Macrakis

    The bug report read
    ~~~~
    taylor(x,x,0,1)*taylor(1/x,x,0,1) => 1/x+... OK
    ~~~~
    but of course the correct result is 1+..., which is what it currently returns. This was probably a typo in the bug report.

    Taylor also now reports (I don't know if it did before) that it is assuming that 1/x+... is zero in the WRONG cases. I don't think that should excuse the incorrect results.

     

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