cosh
The hyperbolic cosine function.
Syntax

cosh(x)

x
is a real or complex number

Description
The hyperbolic cosine function is defined by
cosh(z) = [e^z + e^−z]/2
for all complex z
.
Examples
cosh(0)
1
cosh(1)
1.54308063482
cosh(i)
0.540302305868
Notes
The graph of the hyperbolic cosine function is known as the “catenary”: