SOLUTION: Would be ever so much grateful for help to prove the trigonometric relation in a thoroughly detailed explanation of proof. {{{tan (x/2)= (1-cosx)/ (sinx)}}}

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Question 667155: Would be ever so much grateful for help to prove the trigonometric relation in a thoroughly detailed explanation of proof.

Found 2 solutions by tam144, Edwin McCravy:
Answer by tam144(6)   (Show Source): You can put this solution on YOUR website!
Start from the right side of the equation. Refer to List of Trig Identities
in book titled:"Solving trig equations and inequalities" (Amazon e-book 2010)
1 - cos x = 2 sin^2 x/2 (Identity 11B)
sin x = 2sin x/2.cos x/2 (Identity 10)
Quotient: (1 - cos x)/sin x = (2sin^2 x/2)/(2sin x/2.cos/x/2)
After simplification, the quotient becomes:
!1 - cos x)/sin x = (sin x/2) / (cos x/2) = tg x/2

Answer by Edwin McCravy(20064)   (Show Source): You can put this solution on YOUR website!


Let  = 
which means  = 

Then the identity becomes

 = 

We will work with the right side:
Use the identities  and 

      = 

      = 
  
Use the identity  in the numerator

      = 

      = 

      = 

      = 

Use the identity 

      = 

Substitute  for 

      = 

Edwin

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