Inverse Hyperbolic Functions

Inverse Hyperbolic Sine: ASinh(x),
If x == 0, ASinh(0) = 0,
Else if x >= 0.1, ASinh(x) = Ln(x + SqRt(1 + Sq(x))),
Else if 0 < x < 0.1, ASinh(x) = LnL(x + Sq(x) / SqRt(1 + Sq(x))),
Else if x < 0, ASinh(x) = −ASinh(−x).
See: Inverse Hyperbolic Sine -- From MathWorld
and Wolfram Function Evaluation

Inverse Hyperbolic Cosine: ACosh(x) = Ln(x + SqRt(Sq(x) - 1)),
but an error if x < 1.
See: Inverse Hyperbolic Cosine -- From MathWorld
and Wolfram Function Evaluation

Inverse Hyperbolic Tangent: ATanh(x),
If |x| >= 1, error,
Else if x == 0, ATanh(0) = 0,
Else if 0 < x < 1, ATanh(x) = LnL(2 * x / (1 - x)),
Else if -1 < x < 0, ATanh(x) = −ATanh(−x).
See: Inverse Hyperbolic Tangent -- From MathWorld
and Wolfram Function Evaluation

Inverse Hyperbolic Cotangent: ACoth(x) = ATanh(1/x),
but error if |x| <= 1.
See: Inverse Hyperbolic Cotangent -- From MathWorld
and Wolfram Function Evaluation

Inverse Hyperbolic Secant: ASech(x) = ACosh(1/x),
but ASech(x) is undefined for x <= 0 or x > 1.
See: Inverse Hyperbolic Secant -- From MathWorld
and Wolfram Function Evaluation

Inverse Hyperbolic Cosecant: ACsch(x) = ASinh(1/x),
but ACsch(0) is undefined.
See: Inverse Hyperbolic Cosecant -- From MathWorld
and Wolfram Function Evaluation

See: Transcendental Function Evaluation