Pretty difficult trig proof (identity)

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iRaid
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Homework Statement


[itex]\frac{sin\theta}{1-cos\theta} - \frac{cot\theta}{1+cos\theta} = \frac{1-cos^{3}\theta}{sin^{3}\theta}[/itex]


Homework Equations


Trig identities..


The Attempt at a Solution


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

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

 
on Phys.org
iRaid said:

Homework Statement


[itex]\frac{sin\theta}{1-cos\theta} - \frac{cot\theta}{1+cos\theta} = \frac{1-cos^{3}\theta}{sin^{3}\theta}[/itex]


Homework Equations


Trig identities..


The Attempt at a Solution


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

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.