Bug? acos giving strange output


    Mar 17 2014 | 3:20 pm
    According to the reference input range is (-1,1) and output (-pi,pi). I'm getting (pi,0) as output range.
    Can anyone confirm?

    • Mar 17 2014 | 3:51 pm
      i think the object is working correct (wrong in reference): http://reference.wolfram.com/mathematica/ref/ArcCos.html
    • Mar 18 2014 | 8:40 am
      If you think for a moment about what acos() is doing, it's clear that the output range can only be a half cycle (i.e., 180° or π) when working with reals (i.e., not complex values).
      Mathematically, there is a certain logic in declaring the range [-π/2 .. π/2]. But the standard digital-arithmetic implementation shifts the range to [0 .. π] (see man acos(3)).
      The Max objects for all calculations are simply wrappers around the standard C math libraries, so if in doubt, that's where to look.
    • Mar 18 2014 | 9:17 am
      "If you think for a moment"
      Hehe yes indeed. I might have if my poor brain wasn't so deadline stressed right now!
      So yes, the bug's in the reference, not the object.