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# C3 Trig Identity Question!

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1. Can anyone help? Been stuck for a while...
Thanks!

Prove the identity sinx+cosx=(1-2cos^2x)/(sinx-cosx)
2. (Original post by DonHorizon)
Can anyone help? Been stuck for a while...
Thanks!

Prove the identity sinx+cosx=(1-2cos^2x)/(sinx-cosx)
Start from the RHS, try using
3. (Original post by NotNotBatman)
Start from the RHS, try using
Thanks! That's what I tried to do at first but I just can't seem to get it to work!
4. (Original post by DonHorizon)
Thanks! That's what I tried to do at first but I just can't seem to get it to work!
Could you show what you have done?
5. (Original post by NotNotBatman)
Could you show what you have done?
I got into a position where I had 2sin^2x-1/sinx-cosx
6. (Original post by DonHorizon)
I got into a position where I had 2sin^2x-1/sinx-cosx
try to get (sin^2x - cos^2x) on the top
7. (Original post by DonHorizon)
I got into a position where I had 2sin^2x-1/sinx-cosx
Okay, I've just jotted it down. Easiest way to do it is to start from the RHS and use , then it's straightforward from there.
8. (Original post by NotNotBatman)
Okay, I've just jotted it down. Easiest way to do it is to start from the RHS and use , then it's straightforward from there.
Ahh! I've done it now! Thanks so much!

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