Two recent threads, on floating point precision and on the elegance of asinh, got me to try to play in my favorite interpreted programming language--PostScript. Of course, PS doesn't standardly provide any hyperbolic functions, but they are trivially defined in terms of exp and ln. The problem is with [lack of] precision. PS starts out with only single precision floating point, and then a lot more precision gets thrown away for values near zero. I suppose I could use a power series for values near zero, or maybe use the hyperbolic version of what I think is Gosper's recursive sin function (based on sin(3x) = 3 sin(x) - 4 sin^3(x)) (hyperbolic equivalent: sinh(3x) = 3 sinh(x) + 4 sinh^3(x)). But I wondered why the standard floating point math libraries (at least the ones I know about) don't provide exp(x)-1 and ln(1+x). Each of these functions is approximately x for small x, and so would avoid the loss of precision when adding 1 to a small number. (If one already has hyperbolic functions, then I suppose exp(x)-1 = sinh(x) (1 + sinh(x)/(cosh(x)+1)), and log(1+x) = 2 atanh(x/(2+x)).) --ms