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Hard trig proof

  1. Jun 4, 2008 #1
    I have to prove this:


    I have got it down to this:


    and the book says it can be then further equated to


    but i cant see how that is done :(

    Can someone show me

    Thanks ;)
  2. jcsd
  3. Jun 4, 2008 #2

    Gib Z

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    Multiply every term in the numerator and the denominator by cos^2 x.
  4. Jun 7, 2008 #3
    What do you need to prove about it ? Generally you prove a proposition. Whats your proposition ?
  5. Jun 8, 2008 #4

    Gib Z

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    There was an error in his latex code, if you know how to read latex code click on his latex and you'll see he meant

    \frac{\sec^{2}A}{1-\tan^{2}A} = \sec2A
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