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Homework Help: Trigonometric Identities

  1. Sep 5, 2010 #1
    1. The problem statement, all variables and given/known data

    (Sin 2θ / sinθ) - (cos 2θ/ cos θ) = Sec θ

    just trying to match one side to the other

    2. Relevant equations

    all trig identities

    3. The attempt at a solution

    broke down sin2θ into 2sinθ cosθ then reduced the sinθ in the denominator

    giving me
    sinθ cosθ - cos2θ / cosθ = Secθ

  2. jcsd
  3. Sep 5, 2010 #2
    You are on the right track. It should be clear to you that the next step is to express cos(2t) as in terms of cos(t). What trig identity do you know that will do that?

    Oh, and double check your expression, you may have made a silly math error there.
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