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Core 3 trigonometry proof?? watch

1. 1/(cos A+ Sin A) + 1/ (CosA-SinA) = Tan 2a Cosec A

2. (Original post by APersonYo)
1/(cos A+ Sin A) + 1/ (CosA-SinA) = Tan 2a Cosec A

By getting it into one fraction, then using identities and cancelling things down.
3. (Original post by APersonYo)
1/(cos A+ Sin A) + 1/ (CosA-SinA) = Tan 2a Cosec A

Maybe, try to form a common denominator and make it 1 fraction? .
Then you'll realise you've eliminated one of the terms in the numerator.
Then, let's see what you do .
4. remember that E/F + G/H can be written as { ExH + FxG } / { FxH }
5. (Original post by monk1324)
lhs= (2cosa)/(cos^2a - sin^2a) = 2cosa/cos2a x sina/sina = (2cosasina)/(cos2a) x 1/sina = sin2a/cos2a x 1/sina = tan2a x coseca = rhs

thank you so so so much!!!
6. (Original post by monk1324)
LHS= (2cosA)/(cos^2A - sin^2A) = 2cosA/cos2A x sinA/sinA = (2cosAsinA)/(cos2A) x 1/sinA = sin2A/cos2A x 1/sinA = tan2A x cosecA = RHS
Please don't give full solutions :'(. It is against the rules of the forum.

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