There is nothing wrong with your mathematics, so your book must be wrong: integral tanx dx - Wolfram|Alpha
Looks like you are right.
Hi
my book says the integral of tan x = ln |sec x|
When i do it:
tan x = sin x/cos x
integral sinx/cos x dx
let u = cos x
du = -sin x dx
- du = sin x dx
integral: -(1/u) du
= ln u = -ln cos x
but sec x = 1/cos x
...?
Edit:
Nvm figured it out -.-
- ln cos x = ln cos x^-1
= ln sec x
so they are equivalent....duh
There is nothing wrong with your mathematics, so your book must be wrong: integral tanx dx - Wolfram|Alpha
Looks like you are right.