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Homework Help: Trig Proof

  1. Jun 5, 2008 #1
    Prove:

    [tex]\frac{Sec^{2}\frac{y}{2}}{2} \eqiv \frac{2}{1+x^{2}}[/tex]

    Well i know from the pythagorean identities that tan^{2}x + 1 = sec^{2}x
    so

    [tex]\frac{tan^{2}\frac{y}{2} + 1}{2} \eqiv \frac{2}{1+x^{2}}[/tex]

    But now im stuck!

    If your interested the full qusetion is page 35, question 7 (ii) here:

    http://www.edexcel.org.uk/VirtualContent/105484/GCE_Pure_Maths_C1_C4_Specimen_Paper_MkScheme.pdf

    Can someone point me in the right direction

    Cheerz
     
  2. jcsd
  3. Jun 5, 2008 #2

    tiny-tim

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    Science Advisor
    Homework Helper

    The actual question is:

    Given that x = tan(y/2), prove that dy/dx = 2/(1 + x²).​

    thomas49th, just differentiate both sides of x = tan(y/2). :smile:
     
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