Question

prove that cos9° + sin9°/
cos9° - sin9°
=cos36​

Answer 1

LHS = (Cos9° + Sin9°) / (Cos9° - Sin9°)  

Divide by Nr and Dr  by  Cos9° ...

LHS = (1 + Tan9°) / (1 - Tan9°)

       = (Tan 45° + Tan 9°) / (1 - Tan 45° * Tan 9°)  

       = Tan (45°+9°)  

       = Tan 54°

       = Cot 36°.

Hope it helps

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Answer 2

Answer:

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Step-by-step explanation:

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