Trig Functions Simplified: How to Solve cosx / (1+sinx) | Expert Guide

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SUMMARY

The discussion focuses on simplifying the expression cosx / (1+sinx) to arrive at the final result of sec x - tan x. The solution involves using the difference of squares identity, sec²(x) - tan²(x) = 1, and multiplying the numerator and denominator by (1 - sin(x)). This manipulation leads to the simplification of the expression to (sec x - tan x) / 1, confirming the final answer. Participants emphasize the importance of algebraic manipulation in trigonometric simplifications.

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  • Understanding of trigonometric identities, specifically secant and tangent functions.
  • Familiarity with algebraic manipulation techniques, including the difference of squares.
  • Knowledge of simplifying rational expressions in trigonometry.
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Homework Statement



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.
 
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Do you know what the value of sec^2x-tan^2x is?

The difference of two squares helps too.
 
sec^2 (x) - tan^2 (x) = 1

but nothing's squared in the problem
 
Not until you do some multiplying.

Do you understand what I mean by the difference of two squares?
 
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.
 
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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