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JEE MainMathematicsModerateDefinite Integration

The value
of 
∫02π\mspace2muxsin⁡6x cos4\int_{0}^{2\pi}\mspace{2mu} x\sin^{6}x{\ cos}^{4}⁡x dx is equal to.

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I=∫02π\mspace2muxsin⁡6xcos⁡4xdxI = \int_{0}^{2\pi}\mspace{2mu} x\sin^{6}x\cos^{4}xdx
I=∫02π\mspace2mu(2π−x)sin⁡6xcos⁡4xdxI = \int_{0}^{2\pi}\mspace{2mu}(2\pi - x)\sin^{6}x\cos^{4}xdx
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2I=2π∫02π\mspace2musin⁡6xcos⁡4xdx2I = 2\pi\int_{0}^{2\pi}\mspace{2mu}\sin^{6}x\cos^{4}xdx
2I=4π∫0π\mspace2musin⁡6xcos⁡4xdx2I = 4\pi\int_{0}^{\pi}\mspace{2mu}\sin^{6}x\cos^{4}xdx
I=4π∫0π/2\mspace2musin⁡6xcos⁡4xdxI = 4\pi\int_{0}^{\pi/2}\mspace{2mu}\sin^{6}x\cos^{4}xdx
=4π((5×3×1)(3×1)10×8×6×4×2)×π2=3π2128= 4\pi\left( \frac{(5 \times 3 \times 1)(3 \times 1)}{10 \times 8 \times 6 \times 4 \times 2} \right) \times \frac{\pi}{2} = \frac{3\pi^{2}}{128}

Source: Grass-G / M-13 Mathematics Paper 4 Nov.docx

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