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MHT CET · Maths · Definite Integration

The value of \(\int_{0}^{\pi / 2} \log (\operatorname{cosec} x) d x\) is

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

Answer & Solution

Correct Answer

(A) \(\frac{\pi}{2} \log 2\)

Step-by-step Solution

Detailed explanation

Let \(\quad I=\int_{0}^{\pi / 2} \log (\operatorname{cosec} x) d x\)
\(=\int_{0}^{\pi / 2} \log \left(\frac{1}{\sin x}\right) d x\)
\(=-\int_{0}^{\pi / 2} \log \sin x d x\)
\(=\frac{\pi}{2} \log 2\)
\(\left[\because \int_{0}^{\pi / 2} \log \sin x d x=-\frac{\pi}{2} \log 2\right]\)