Changes

*This function gives the Inverse Hyperbolic Cosine of a number.  

*This function gives the Inverse Hyperbolic Cosine of a number.  

*Here 'z' is  any positive real number i.e, z >= 1 .  

*Here 'z' is  any positive real number i.e, <math>z \ge 1</math>.  

*Inverse Hyperbolic sine of a number is defined by <math>Acosh(z)=log e(z+\sqrt(z^2-1)</math>

*Inverse Hyperbolic sine of a number is defined by <math>Acosh(z)=log e(z+\sqrt(z^2-1)</math>

*ACOSH(-2)=NAN , since z>2

*ACOSH(-2)=NAN , since z>2