acosh-Hyperbolic Arc Cosine of Angle

Interface

F_TYPE acosh (F_TYPE x)

Description

acosh() returns the hyperbolic arc cosine of x for x in the interval [1,+infinity], where acosh(x) = ln(x + sqrt(x**2 -1)). acosh() is the inverse function of cosh(), where acosh(cosh (x)) = x.

Exceptions

Exceptional Argument       Routine Behavior

x<1                        Invalid argument