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JEE Mains · Maths · STD 12 - 7.2 definite integral

If \(\int_0^{\frac{\pi }{2}} {\frac{{\cot \,x}}{{\cot \,x + \cos ec\,x}}} dx = m\left( {\pi  + n} \right)\), then \(m.n\) is equal to

  1. A \(1\)
  2. B \(\frac{1}{2}\)
  3. C \(-\frac{1}{2}\)
  4. D \(-1\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(-1\)

Step-by-step Solution

Detailed explanation

\(\int_{0}^{\pi / 2} \frac{\cot x d x}{\cot x+\csc x}\) \(\int_{0}^{\pi / 2} \frac{\cos x}{\cos x+1}=\int \frac{2 \cos ^{2} \frac{x}{2}-1}{2 \cos ^{2} \frac{x}{2}}\) \(\int_{0}^{\pi / 2}\left(1-\frac{1}{2} \sec ^{2} \frac{x}{2}\right) d x\)…