JEE Mains · Maths · STD 12 - 7.2 definite integral
If \(\displaystyle\int_{\pi/6}^{\pi/4}\left(\cot\left(x-\dfrac{\pi}{3}\right)\cot\left(x+\dfrac{\pi}{3}\right)+1\right)dx = \alpha\log_e(\sqrt{3}-1)\), then \(9\alpha^2\) is equal to ________.
- A 12
- B 24
- C 46
- D 48
Answer & Solution
Correct Answer
(A) 12
Step-by-step Solution
Detailed explanation
Given integral is \(I = \displaystyle\int_{\pi/6}^{\pi/4}\left(\cot\left(x-\dfrac{\pi}{3}\right)\cot\left(x+\dfrac{\pi}{3}\right)+1\right)dx\) Using the identity \(\cot A \cot B + 1 = \dfrac{\cos(A-B)}{\sin A \sin B}\), the integrand simplifies to:…
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