Csch-func
The cosh(x) function returns hyperbolic cosecant of x.
double csch(double x)
x
The function returns the hyperbolic cosecant of x. For zero and absolute values greater than 710 the function returns missing value.
csch(-10)=; //should return -9.0799859712122E-5
sinh, cosh, tanh, coth, sech,