Hi I need help in proving trigonometric identities.

The qn is Prove the identity:

tan x/ 1 + cos x + tan x/1 - cos x = 2 (tan x + cot x )

Thanks (;

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- Nov 1st 2008, 11:31 PMSniperMarksmanTrigonometry Identities
Hi I need help in proving trigonometric identities.

The qn is Prove the identity:

tan x/ 1 + cos x + tan x/1 - cos x = 2 (tan x + cot x )

Thanks (; - Nov 2nd 2008, 12:32 AMmr fantastic
LHS $\displaystyle = \frac{\tan x}{1 + \cos x} + \frac{\tan x}{1 - \cos x}$

$\displaystyle = \frac{\tan x (1 - \cos x) + \tan x (1 + \cos x)}{(1 + \cos x) (1 - \cos x)}$

Numerator: Substitute $\displaystyle \tan x = \frac{\sin x}{\cos x}$ and expand.

Denominator: Note the $\displaystyle (1 + \cos x) (1 - \cos x) = 1 - \cos^2 x = \sin^2 x$.

Continue simplifying until recognise that you've clearly got the RHS. - Nov 2nd 2008, 12:35 AMSniperMarksman
O.o alright, thanks =D

- Nov 2nd 2008, 01:01 AMAngelAngel (BestSolution)
Still not proving..........please solve it completely please...............

- Nov 2nd 2008, 01:16 AMmr fantastic
- Nov 2nd 2008, 05:51 AMCaptainBlack