pub fn atanh(x: f64) -> f64
Inverse hyperbolic tangent (f64)
Calculates the inverse hyperbolic tangent of x. Is defined as log((1+x)/(1-x))/2 = log1p(2x/(1-x))/2.
x
log((1+x)/(1-x))/2 = log1p(2x/(1-x))/2