CommandssechOn this pagesech sech (x) The sech function returns the hyperbolic secant of x. csch(x)=1cosh(x)=2ex+e−x.\displaystyle \operatorname{csch}(x)=\frac{1}{\cosh (x)}=\frac{2}{e^{x}+e^{-x}} .csch(x)=cosh(x)1=ex+e−x2. In complex expressions, x is complex, and sech(x) returns a complex value. See Also cosh, tanh, coth, csch