> | 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