Definite Integration Question 392

Question: If $ I_1=\int_e^{e^{2}}{\frac{dx}{\log x}} $ and $ I_2=\int_1^{2}{\frac{e^{x}}{x}dx,} $ then

[Karnataka CET 2000]

Options:

A) $ I_1=I_2 $

B) $ I_1>I_2 $

C) $ I_1<I_2 $

D) None of these

Show Answer

Answer:

Correct Answer: A

Solution:

Put $ \log x=u $ in $ I_1, $ so that $ dx=xdu=e^{u}du $

Also as $ x=e $ to $ e^{2},u=1 $ to 2 Thus, $ I_1=\int_1^{2}{\frac{e^{u}}{u}du=\int_1^{2}{\frac{e^{x}}{x}dx}} $ .

Hence, $ I_1=I_2 $ .