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Trig algebra

  1. Dec 8, 2009 #1
    1. The problem statement, all variables and given/known data
    (1 + tg(x)) * cos^2(x) > 1, solve the inequality


    2. Relevant equations
    tg(x) = sin(x)/cos(x)
    cos(x) * sin(x) = 1/2 sin(2x)



    3. The attempt at a solution
    I got my final value of:
    1-sin^2(x) + 1/2 sin(2x) > 1
    but because of the 2 inside the sin
    I'm kinda lost so I can't use quadratic formula I presume
     
  2. jcsd
  3. Dec 8, 2009 #2
    Let me rearrange that a little for you:

    1/2sin(2x)>sin^2(x)

    which is actually nicer in the following form:

    sin(x)cos(x)>sin^2(x).

    This should be easier to solve.
     
  4. Dec 8, 2009 #3
    It is important for you to realize where this came from.
    If you have notes, cheat sheet, book, or webpage with trig identities, look at the double angle identities.



    [tex]sin2x=2sinxcosx[/tex]
     
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