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JEE Mains · Maths · STD 12 - 7.2 definite integral

\(\left|\frac{120}{\pi^3} \int_0^\pi \frac{x^2 \sin x \cos x}{\sin ^4 x+\cos ^4 x} d x\right|\) is equal to ...........

  1. A \(15\)
  2. B \(16\)
  3. C \(17\)
  4. D \(18\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(15\)

Step-by-step Solution

Detailed explanation

\(\int_0^\pi \frac{x^2 \sin x \cdot \cos x}{\sin ^4 x+\cos ^4 x} d x\) \(=\int_0^{\frac{\pi}{2}} \frac{\sin x \cdot \cos x}{\sin ^4 x+\cos ^4 x}\left(x^2-(\pi-x)^2\right) d x\) \(=\int_0^{\frac{\pi}{2}} \frac{\sin x \cdot \cos x\left(2 \pi x-\pi^2\right)}{\sin ^4 x+\cos ^4 x}\)…