Derivative of Inverse Hyperbolic Tangent Function

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Theorem

Let $u$ be a differentiable real function of $x$.

Then:

$\map {\dfrac \d {\d x} } {\artanh u} = \dfrac 1 {1 - u^2} \dfrac {\d u} {\d x}$

where $\size u < 1$

where $\tanh^{-1}$ is the real area hyperbolic tangent.


Proof

\(\ds \map {\frac \d {\d x} } {\artanh u}\) \(=\) \(\ds \map {\frac \d {\d u} } {\artanh u} \frac {\d u} {\d x}\) Chain Rule for Derivatives
\(\ds \) \(=\) \(\ds \dfrac 1 {1 - u^2} \frac {\d u} {\d x}\) Derivative of Inverse Hyperbolic Tangent

$\blacksquare$


Also see


Sources