The inverse hyperbolic tangent calculator computes artanh(x) (also written as tanhโปยน(x) or atanh(x)) for values strictly between โ1 and 1. The formula is artanh(x) = ยฝ ln((1+x)/(1โx)). This function appears in special relativity, statistics (Fisher z-transformation), and electromagnetism.
Inverse Hyperbolic Tangent Calculator
Domain: โ1 < x < 1 (exclusive)
What is Inverse Hyperbolic Tangent?
Inverse hyperbolic tangent (artanh or tanhโปยน) returns the value whose hyperbolic tangent equals the input.
- Domain: (โ1, 1) โ strictly between โ1 and 1
- Range: all real numbers (โโ, +โ)
- Formula: artanh(x) = ยฝ ln((1+x)/(1โx))
- Odd function: artanh(โx) = โartanh(x)
- Derivative: d/dx[artanh(x)] = 1/(1 โ xยฒ)
How to Calculate Inverse Hyperbolic Tangent
The calculations inside an inverse hyperbolic tangent (artanh) fundamentally map ratios confined firmly between boundary limits toward potentially infinite continuous spaces.
To compute correctly natively spanning across log equations, physicists leverage the absolute formula expression:
artanh(x) = (1/2) * ln((1 + x) / (1 − x))
The derivative showcases incredible alignment with rational mathematics: d/dx [artanh(x)] = 1 / (1 − x²) for any variable structurally constrained inside (−1, 1).
Difference between Hyperbolic Tangent and its Inverse
- Hyperbolic Tangent (tanh): Compresses wide exponential infinities rigidly within asymptotes at −1 and 1. Highly prevalent in neural network smoothing layers.
- Inverse Hyperbolic Tangent (artanh): Performs the geometric explosion trickโconverting strict fractional bounds [−1, 1] into wildly sprawling infinities traversing all real ranges.
Real-Life Applications
The function is intensely pivotal across a myriad of cutting edge physical technologies:
- Fluid Dynamics: Computing precise timeline velocities for large falling objects accounting completely accurately for aerodynamic air resistance terminal velocity matrices.
- Artificial Intelligence: Transforming and stretching normalized bounded activation layers back into continuous variables within backpropagation gradients.
Common Values
Click any row to calculate.
| x | artanh(x) | Exact Form |
|---|---|---|
| โ0.9 | โ1.4722 | ยฝ ln(1/19) |
| โ0.5 | โ0.5493 | โยฝ ln(3) |
| 0 | 0 | 0 |
| 0.25 | 0.2554 | ยฝ ln(5/3) |
| 0.5 | 0.5493 | ยฝ ln(3) |
| 0.75 | 0.9730 | ยฝ ln(7) |
| 0.9 | 1.4722 | ยฝ ln(19) |
Frequently Asked Questions
artanh(x) approaches ยฑโ as x approaches ยฑ1. The function has vertical asymptotes at x = โ1 and x = 1. At these points, the logarithm becomes undefined.
The Fisher z-transformation is exactly artanh(r), where r is a correlation coefficient. It converts correlations (bounded in [โ1,1]) to unbounded values for statistical analysis.
Use =ATANH(value) in Excel. Or use the formula: =0.5*LN((1+x)/(1-x)).
arctan is the inverse of circular tangent (accepts all reals, returns angles). artanh is the inverse of hyperbolic tangent (accepts (โ1,1), returns all reals).
artanh(0) = 0. Because tanh(0) = 0, and ยฝ ln(1/1) = ยฝ ln(1) = 0.