Integral Calculus Question 50

Question: $ \int_{{}}^{{}}{\frac{x\ dx}{(x^{2}-a^{2})(x^{2}-b^{2})}=} $

[Roorkee 1976]

Options:

A) $ \frac{1}{a^{2}-b^{2}}\log ( \frac{x^{2}-a^{2}}{x^{2}-b^{2}} )+c $

B) $ \frac{1}{a^{2}-b^{2}}\log ( \frac{x^{2}-b^{2}}{x^{2}-a^{2}} )+c $

C) $ \frac{1}{2(a^{2}-b^{2})}\log ( \frac{x^{2}-a^{2}}{x^{2}-b^{2}} )+c $

D) $ \frac{1}{2(a^{2}-b^{2})}\log ( \frac{x^{2}-b^{2}}{x^{2}-a^{2}} )+c $

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Answer:

Correct Answer: C

Solution:

$ \int_{{}}^{{}}{\frac{x}{(x^{2}-a^{2})(x^{2}-b^{2})}},dx $ $ =\frac{1}{a^{2}-b^{2}}[ \int_{{}}^{{}}{\frac{x}{x^{2}-a^{2}},dx-\int_{{}}^{{}}{\frac{x,dx}{x^{2}-b^{2}}}} ] $ .