2 asinh - inverse hyperbolic sine
9 eps nonzero real, defaults to epsilon()
14 Returns the asinh of x to a multiple of eps with error less in
15 absolute value than .75 * eps.
17 asinh(x) is the real number v for which sinh(v) = x. It is given by
19 asinh(x) = ln(x + sqrt(1 + x^2))
22 > print asinh(2, 1e-5), asinh(2, 1e-10), asinh(2, 1e-15), asinh(2, 1e-20)
23 1.44363 1.4436354752 1.44363547517881 1.44363547517881034249
29 NUMBER *qasinh(NUMBER *x, NUMBER *eps)
32 acosh, atanh, asech, acsch, acoth, epsilon