> | sinh x = (exp(x) - exp(-x))/2 > | cosh x = (exp(x) + exp(-x))/2 ... > This looks pretty reasonable to me. We should have default methods > for anything we can. Why not provide defaults for the inverse functions as well? asinh x = log (x + sqrt (1+x*x)) acosh x = log (x + (x+1) * sqrt ((x-1)/(x+1))) atanh x = log ((x+1) / sqrt (1 - x*x)) -- Lennart