What is the integration of secx dx ?

1 Answer
Mar 24, 2018

Multiply and divide by, #sec x+tan x#

#int sec x dx = int (sec x (sec x+tan x))/(sec x+tan x) dx #

#= int (sec^2 x+sec x tan x)/(sec x+tan x) dx #

let #sec x+tan x =t#
therefore, #dt = (sec^2 x+sec x tan x)dx#

#= int dt/t#

#= ln |t| + C#

#= ln | sec x + tan x| + C#