Integral Calculus Question 41

Question: $ \int_{{}}^{{}}{\frac{dx}{x+x\log x}=} $

[MP PET 1993; Roorkee 1977]

Options:

A) $ \log (1+\log x) $

B) $ \log \log (1+\log x) $

C) $ \log x+\log (\log x) $

D) None of these

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Answer:

Correct Answer: A

Solution:

$ \int_{{}}^{{}}{\frac{dx}{x+x\log x}}=\int_{{}}^{{}}{\frac{dx}{x(1+\log x)}} $ Now putting $ 1+\log x=t\Rightarrow \frac{1}{x},dx=dt, $ it reduces to $ \int_{{}}^{{}}{\frac{dt}{t}}=\log (t)=\log (1+\log x) $ .