1. ## Identity Problem

Hi guys, I'm 14, and was just wondering if anyone could help prove this problem on my homework sheet.

(1+sec x + tan x)(1 - sec x + tan x) = 2 tan x

Thanks

2. ## Re: Identity Problem

Originally Posted by HerroDere
Hi guys, I'm 14, and was just wondering if anyone could help prove this problem on my homework sheet.

(1+sec x + tan x)(1 - sec x + tan x) = 2 tan x

Thanks
start by expanding the left side of the identity ... then use the identity $\displaystyle 1 + \tan^2{x} = \sec^2{x}$ when collecting terms.

3. ## Re: Identity Problem

Originally Posted by HerroDere
(1+sec x + tan x)(1 - sec x + tan x) = 2 tan x
Hint: $\displaystyle (1+\sec(x) + \tan (x))(1 - \sec (x) + \tan( x))$=
$\displaystyle (1+\tan(x))^2-\sec^2(x)$