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Let ∫dx(x−x−1)2=αu(x)+βv(x)+C\int \frac{dx}{\left(\sqrt{x} - \sqrt{x-1}\right)^2} = \alpha u(x) + \beta v(x) + C, where u(x)=x2−x+(x−12)x2−xu(x) = x^2 - x + \left(x - \frac{1}{2}\right)\sqrt{x^2 - x} and v(x)=log⁡∣x−12+x2−x∣v(x) = \log\left|x - \frac{1}{2} + \sqrt{x^2 - x}\right|. The value of α+β\alpha + \beta is :

Solution

✅ Correct Option: 1

Rationalize: 1(x−x−1)2=(x+x−1)2=2x−1+2x2−x\frac{1}{(\sqrt{x} - \sqrt{x-1})^2} = (\sqrt{x} + \sqrt{x-1})^2 = 2x - 1 + 2\sqrt{x^2 - x}. Integrating: x2−x+2∫x2−x dxx^2 - x + 2\int\sqrt{x^2-x}\,dx. With x2−x=(x−1/2)2−1/4x^2-x = (x-1/2)^2 - 1/4, 2∫x2−x dx=(x−1/2)x2−x−14log⁡∣x−1/2+x2−x∣2\int\sqrt{x^2-x}\,dx = (x-1/2)\sqrt{x^2-x} - \frac{1}{4}\log|x-1/2 + \sqrt{x^2-x}|. So total =u(x)−14v(x)+C= u(x) - \frac{1}{4}v(x) + C. Hence α=1\alpha = 1, β=−14\beta = -\frac{1}{4}, α+β=34\alpha + \beta = \frac{3}{4}.

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