Primitive of Square of Sine Function/Corollary

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Corollary to Primitive of Square of Sine Function

$\ds \int \sin^2 x \rd x = \frac {x - \sin x \cos x} 2 + C$

where $C$ is an arbitrary constant.


Proof

\(\ds \int \sin^2 x \rd x\) \(=\) \(\ds \frac x 2 - \frac {\sin 2 x} 4 + C\) Primitive of Square of Sine Function
\(\ds \) \(=\) \(\ds \frac x 2 - \frac {2 \sin x \cos x} 4 + C\) Double Angle Formula for Sine
\(\ds \) \(=\) \(\ds \frac {x - \sin x \cos x} 2 + C\)

$\blacksquare$


Sources