Arccosecant Logarithmic Formulation

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Theorem

Let $x$ be a real number.

Let $x \in \hointl {-\infty} {-1} \cup \hointr 1 {\infty}$.


Then:

$\arccsc x = -i \map \Ln {\sqrt {1 - \dfrac 1 {x^2} } + \dfrac i x}$

where:

$\arccsc$ is the arccosecant function
$\Ln$ is the principal branch of the complex logarithm whose imaginary part lies in $\hointl {-\pi} \pi$.


Proof

\(\ds \arccsc x\) \(=\) \(\ds \map \arcsin {\frac 1 x}\) Arccosecant of Reciprocal equals Arcsine
\(\ds \) \(=\) \(\ds -i \map \Ln {\sqrt {1 - \paren {\frac 1 x}^2} + i \times \frac 1 x}\) Arcsine Logarithmic Formulation
\(\ds \) \(=\) \(\ds -i \map \Ln {\sqrt {1 - \frac 1 {x^2} } + \frac i x}\)

$\blacksquare$


Also see