Integral Calculus Question 168

Question: $ \int_{{}}^{{}}{\frac{1+\tan x}{x+\log \sec x}\ dx=} $

[AI CBSE 1986]

Options:

A) $ \log (x+\log \sec x)+c $

B) $ -\log (x+\log \sec x)+c $

C) $ \log (x-\log \sec x)+c $

D) None of these

Show Answer

Answer:

Correct Answer: A

Solution:

Put $ t=x+\log \sec x\Rightarrow dt=(1+\tan x),dx, $ then $ \int_{{}}^{{}}{\frac{1+\tan x}{x+\log \sec x},dx=\int_{{}}^{{}}{\frac{1}{t},dt=\log t+c}} $ $ =\log (x+\log \sec x)+c. $