int sqrt{x-1}(x sqrt{x+1})^{-1} d x= | vedclass

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(A) $I = \int \frac{\sqrt{x-1}}{x \sqrt{x+1}} dx = \int \frac{1}{x} \sqrt{\frac{x-1}{x+1}} dx$Let $\sqrt{\frac{x-1}{x+1}} = t$. Then $\frac{x-1}{x+1}

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$\ln \left|x+\sqrt{x^2-1}\right|-\sec ^{-1}(x)+c$

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(A) $I = \int \frac{\sqrt{x-1}}{x \sqrt{x+1}} dx = \int \frac{1}{x} \sqrt{\frac{x-1}{x+1}} dx$Let $\sqrt{\frac{x-1}{x+1}} = t$. Then $\frac{x-1}{x+1} = t^2$.Solving for $x$: $x-1 = t^2x + t^2 \Rightarrow x(1-t^2) = 1+t^2 \Rightarrow x = \frac{1+t^2}{1-t^2}$.Differentiating with respect to $t$: $dx = \frac{(1-t^2)(2t) - (1+t^2)(-2t)}{(1-t^2)^2} dt = \frac{4t}{(1-t^2)^2} dt$.Substituting into the integral: $I = \int \left(\frac{1-t^2}{1+t^2}ight) \cdot t \cdot \frac{4t}{(1-t^2)^2} dt = \int \frac{4t^2}{(1+t^2)(1-t^2)} dt$.Using partial fractions: $\frac{4t^2}{(1+t^2)(1-t^2)} = \frac{2}{1-t^2} - \frac{2}{1+t^2}$.Integrating: $I = 2 \int \frac{1}{1-t^2} dt - 2 \int \frac{1}{1+t^2} dt = 2 \left( \frac{1}{2} \ln \left| \frac{1+t}{1-t} ight| ight) - 2 	an^{-1}(t) + c = \ln \left| \frac{1+t}{1-t} ight| - 2 	an^{-1}(t) + c$.Substituting $t = \sqrt{\frac{x-1}{x+1}}$: $I = \ln \left| \frac{\sqrt{x+1}+\sqrt{x-1}}{\sqrt{x+1}-\sqrt{x-1}} ight| - 2 	an^{-1} \sqrt{\frac{x-1}{x+1}} + c$.Rationalizing the log term: $\ln \left| \frac{(\sqrt{x+1}+\sqrt{x-1})^2}{(x+1)-(x-1)} ight| = \ln \left| \frac{2x + 2\sqrt{x^2-1}}{2} ight| = \ln \left| x + \sqrt{x^2-1} ight|$.For the inverse trig term: $2 	an^{-1} \sqrt{\frac{x-1}{x+1}} = \sec^{-1}(x)$.Thus,$I = \ln \left| x + \sqrt{x^2-1} ight| - \sec^{-1}(x) + c$.

$\int \sqrt{x-1}(x \sqrt{x+1})^{-1} d x=$

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