Primitive of Cosecant Function

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Theorem

Tangent Form

$\ds \int \csc x \rd x = \ln \size {\tan \frac x 2} + C$

where $\tan \dfrac x 2 \ne 0$.


Cosecant plus Cotangent Form

$\ds \int \csc x \rd x = -\ln \size {\csc x + \cot x} + C$

where $\csc x + \cot x \ne 0$.


Cosecant minus Cotangent Form

$\ds \int \csc x \rd x = \ln \size {\csc x - \cot x} + C$

where $\csc x - \cot x \ne 0$.


Also presented as

Some sources present this result as the primitive of the reciprocal of the sine function:

\(\ds \int \dfrac {\d x} {\sin x}\) \(=\) \(\ds \ln \size {\tan \frac x 2} + C\)
\(\ds \int \dfrac {\d x} {\sin x}\) \(=\) \(\ds -\ln \size {\csc x + \cot x} + C\)
\(\ds \int \dfrac {\d x} {\sin x}\) \(=\) \(\ds \ln \size {\csc x - \cot x} + C\)


Also see