Author: Andreas Rossberg
Last revised: August 22, 2015
Status: proposed
Discussion:issue #9

signature MATH

This proposal adds the inverse hyperbolic functions to theMATH signature.

val asinh : real -> realval acosh : real -> realval atanh : real -> real

• asinh x
  returns the arc hyperbolic sine ofx, expressed in radians. It is the inverse of thesinh function.

• acosh x
  returns the nonnegative arc hyperbolic cosine ofx, expressed in radians.It is the inverse of thecosh function.Ifx < 1.0, then theDomain exception is raised.

• atanh x
  returns the arc hyperbolic tangent ofx, expressed in radians.It is the inverse of thetanh function.TheDomain exception is raised ifx <= ~1.0 or1.0 <= x.

These functions are fairly standard in contemporary languages' math libraries.

The addition of these functions should not affect existing programs.

• [2015-08-22] Added more detailed description of functions and made some formattingchanges for consistency.[JHR].

• [2015-08-16] Proposed