Question

prove that: Cos x /1-Sin x= Cot ( π/4- x/2)
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Answer 1

Answer:

cosx/1-sinx=(cos²x/2-sin²x/2)/(cosx/2-sinx/2)²

=(cosx/2+sinx/2)/cosx/2-sinx/2

by dividing numerator and denominator with sinx/2 we get

(cotx/2+1)/cotx/2-1

=cot(π/4-x/2)