Pretty difficult trig proof (identity)

AI Thread Summary
The discussion revolves around a trigonometric identity proof involving the equation sin(θ)/(1-cos(θ)) - cot(θ)/(1+cos(θ)) = (1-cos³(θ))/sin³(θ). Participants highlight the importance of correctly interpreting the cotangent function and emphasize the need for clarity in the steps taken to solve the problem. One user expresses confusion about their progress, while another points out a mistake in factoring out sin(θ) in the numerator. The conversation underscores the collaborative nature of problem-solving in mathematics, with members providing guidance without directly giving away solutions. The thread concludes with a realization of simple errors that can hinder progress in solving trigonometric identities.
iRaid
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Homework Statement


\frac{sin\theta}{1-cos\theta} - \frac{cot\theta}{1+cos\theta} = \frac{1-cos^{3}\theta}{sin^{3}\theta}


Homework Equations


Trig identities..


The Attempt at a Solution


Basically I got to:
\frac{sin\theta+(cos^{2}\theta)(sin\theta)}{sin^{2}\theta}

Homework Statement



Is that right up to there, I think not because I can't get passed this lol.


Homework Equations





The Attempt at a Solution

 
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That doesn't look right.

Show how you got your result so we can help you.
 
iRaid said:

Homework Statement


\frac{sin\theta}{1-cos\theta} - \frac{cot\theta}{1+cos\theta} = \frac{1-cos^{3}\theta}{sin^{3}\theta}


Homework Equations


Trig identities..


The Attempt at a Solution


Basically I got to:
\frac{sin\theta+(cos^{2}\theta)(sin\theta)}{sin^{2}\theta}

Homework Statement



Is that right up to there, I think not because I can't get passed this lol.


Homework Equations





The Attempt at a Solution


You did notice the cot function did you - or did you misread it as cos?
 
I don't think you were supposed to solve the question for the Original Poster!
 
Last edited by a moderator:
>_> Oh. Well, I hope my explanation blurb thing helps so that I'm not just blatantly giving the solution without providing any real understanding.
 
Dr. Seafood said:
>_> Oh. Well, I hope my explanation blurb thing helps so that I'm not just blatantly giving the solution without providing any real understanding.
PeterO is correct. The Physics Forums rules do not permit a member to post the solution to another member's problem.
 
OK, I attached the rest of my work..
 

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iRaid said:
OK, I attached the rest of my work..

In your 5th line, when you took out a factor of sin(theta) in the numerator, it was not a common factor, as it was in the denominator of a couple of the terms.
 
PeterO said:
In your 5th line, when you took out a factor of sin(theta) in the numerator, it was not a common factor, as it was in the denominator of a couple of the terms.

I see now thanks, I got it. Stupid mistakes.
 
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