On Thu, 26 Feb 2009, Jon Lang wrote: > asin is not the inverse function of sin, although it's probably as close > as you can get. And even there, some sort of compiler optimization could > potentially be done, replacing the composition of asin and sin (both of > which have the potential to intensify error) with a normalization of the > value into the -pi ..^ pi range (which might also introduce error).
Hmmm ... the normal mathematical range of arc-sine is (-π,+π], rather than [-π,+π), especially where complex numbers are concerned: arg(-1) == +π. (Well, so much for consistently using lower half-open ranges.) -Martin
