# Trig Functions question

by mjbc
Tags: functions, trig
 P: 4 1. The problem statement, all variables and given/known data Simplify: cosx / (1+sinx) 2. The attempt at a solution 1 / (sec x)(1+sin x) 1 / (sec x + (sin x / cos x)) 1 / (sec x + tan x) I know that the answer is sec x - tan x but don't know how to get there. Any help would be appreciated.
 P: 123 Do you know what the value of $$sec^2x-tan^2x$$ is? The difference of two squares helps too.
 P: 4 sec^2 (x) - tan^2 (x) = 1 but nothing's squared in the problem
 P: 123 Trig Functions question Not until you do some multiplying. Do you understand what I mean by the difference of two squares?
 Sci Advisor HW Helper Thanks P: 25,228 You could also just multiply top and bottom of your given expression by (1-sin(x)) and expand. It's really the same thing as jing is suggesting.
 P: 4 OK, So it's (sec x - tan x) / (sec x + tan x)(sec x -tan x) = (sec x - tan x) / 1 = sec x -tan x Thank you so much!!

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