This is fron R-2.5.0-to-be, windows XP The following excerpt from ?asin cannot be right: For asin() and acos(), there are two cuts, both along the real axis: *(-Inf, 1]* and *[1, Inf)*. Functions asin() and acos() are continuous from above on the interval *(-Inf, -1]* and continuous from below on *[1, Inf)*. Note the first interval should be (-Inf, -1) not (-Inf, 1) Kjetil [[alternative HTML version deleted]]