[Octave-bug-tracker] [bug #44280] asin, asind, atan, and atand may have incorrect values

[anonymous]

URL:
  <http://savannah.gnu.org/bugs/?44280>

                 Summary: asin, asind, atan, and atand may have incorrect
values
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Tue 17 Feb 2015 01:31:28 AM UTC
                Category: Octave Function
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: jeff pantazes
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 3.8.1
        Operating System: Mac OS

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Details:

GNU Octave, version 3.8.1
Octave was configured for "x86_64-apple-darwin14.1.0".

octave --eval "asind(3)" yields 90.000 + 100.998i
however wolfram alpha yields 
89.999999999999...-100.9979734210524220... i
Please note the negative sign next to the imaginary number.
My personal calculations give 90 + -100.997973421052i
Again I am noting the negative sign not the rounding.

Found same for:
octave --eval "atand(5i)"
result: -90.000 + 11.616i
wolfram alpha: 
89.99999999... + 11.61571971720673661409100... i
personal:
90+11.6157197172067i
note the -90 instead of 90

atan(5i)
octave: -1.57080 + 0.20273i
wolfram alpha: 1.5707963267... + 0.20273255... i
personal: 1.570796326+0.202732554i

asin(3)
octave: 1.5708 + 1.7627i
wolfram alpha: 1.570796326... -1.7627471740... i
personal: 1.570796326+-1.76274717i

Most likely I am in error, if so I apologize ahead of time.  Thanks for
looking at this.







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