The
.BR acosh ()
function calculates the inverse hyperbolic cosine of
-\fIx\fP; that is the value whose hyperbolic cosine is \fIx\fP.
+.IR x ;
+that is the value whose hyperbolic cosine is
+.IR x .
.SH RETURN VALUE
On success, these functions return the inverse hyperbolic cosine of
.IR x .
.BR cosh (3),
.BR sinh (3),
.BR tanh (3)
+.SH COLOPHON
+This page is part of release 3.79 of the Linux
+.I man-pages
+project.
+A description of the project,
+information about reporting bugs,
+and the latest version of this page,
+can be found at
+\%http://www.kernel.org/doc/man\-pages/.