Question: If $\int e^{\sec x}\left(\sec x \tan x f(x)+\left(\sec x \tan x+\sec ^{2} x\right) d x=\right.$
$e^{\sec x} f(x)+C$, then a possible choice of $f(x)$ is :-
$\sec x-\tan x-\frac{1}{2}$
$x \sec x+\tan x+\frac{1}{2}$
$\sec x+x \tan x-\frac{1}{2}$
$\sec x+\tan x+\frac{1}{2}$
Correct Option: , 4
Solution:
