If ∫ sec x (sec x tan x f(x) + (sec x tan x + sec2 x)) dx = esecx f(x) + C, then a possible choice o f(x) is :
(1) secx – tanx - 1/2
(2) secx + xtanx - 1/2
(3) secx + tanx + 1/2
(4) xsecx + tanx + 1/2
Correct option (3) secx + tanx + 1/2
Explanation: