Prove..

Prove: cot A - tan A = 2 cot 2A

Hence prove

tan A+2tan2A+4tan4A+8 Cot 8A =Cot A

1 Answers

Very simple expand 8 cot8A = 4(cot4A - tan4A)
Hence 4tan4A will be cancelled
4cot4A = 2(Cot2A - Tan2A)

Therefore 2Tan2A will be cancelled .
Then 2Cot2A = Cot A -TanA .
Tan A is cancelled left is Cot A

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