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Homework Help: Secant, tangent

  1. Jan 25, 2012 #1
    1. The problem statement, all variables and given/known data

    Screenshot2012-01-25at35053AM.png

    2. Relevant equations



    3. The attempt at a solution

    I don't see how they get from step one to two. I would think both secants would cancel since one is positive and the other is negative but that doesn't happen. i think i understand the manipulations of the tangents but not entirely
     
  2. jcsd
  3. Jan 25, 2012 #2
    its simple. just expand the numerator and then take sec x common
     
  4. Jan 25, 2012 #3
    ok, I get it

    ab - ac = a(b-c)
     
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