Value of $\int\left(\frac{1}{\log x}-\frac{1}{(\log x)^2}\right)dx$ is
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → $\frac{x}{\log x} + c$, where c is an arbitrary constant
$I = \int \left(\frac{1}{\log x} - \frac{1}{(\log x)^2}\right) \, dx$
Let $\log x = t \Rightarrow dx = e^t \, dt$.
$I = \int \frac{1}{t} e^t \, dt - \int \frac{1}{t^2} e^t \, dt$
Using integration by parts for the second term:
$\int \frac{1}{t^2} e^t \, dt = -\frac{e^t}{t} + \int \frac{e^t}{t} \, dt$
Combining both integrals:
$I = \int \frac{e^t}{t} \, dt - \left(-\frac{e^t}{t} + \int \frac{e^t}{t} \, dt\right)$
$= \frac{e^t}{t} = \frac{x}{\log x} + C$