Changes between Version 12 and Version 13 of Ticket #24428


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Timestamp:
02/20/18 08:39:33 (3 years ago)
Author:
jdemeyer
Comment:

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  • Ticket #24428

    • Property Summary changed from Substitution should be the same as numerical evaluation to Numerical evaluation should return a complex number if applicable
  • Ticket #24428 – Description

    v12 v13  
    1 It is very surprising that these do not give the same result:
     1This looks wrong:
    22{{{
    33sage: arccosh(0.9)
    44NaN
    55}}}
    6 and
     6
     7Especially given all the following:
     8{{{
     9sage: arccosh(RDF(0.9))
     100.45102681179626236*I
     11}}}
     12
    713{{{
    814sage: arccosh(x).subs(x=0.9)
     
    1016}}}
    1117
    12 The second result is more useful, so the first should probably return a complex number too.
     18{{{
     19sage: sqrt(-2.0)
     201.41421356237310*I
     21}}}
    1322
    14 See also
    15 {{{
    16 sage: arccosh(RDF(0.9))
    17 0.45102681179626236*I
    18 }}}
     23A complex number is more useful than a `NaN` so we shouldn't return `NaN` in the first example.