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Show that $$ \tan(A)=\frac{\sin2A}{1+\cos 2A} $$

I've tried a few methods, and it stumped my teacher.

  • 1
    Failure to prove is not surprising. It is quite false. For example, take $A=\pi/4$ ($45$ degrees).2012-03-15
  • 0
    I think you want $\cos(2A)$ there...2012-03-15
  • 0
    This is not a valid identity: try $A=\pi/4$ for example.2012-03-15

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