Anyone with University level Trig knowledge?

Discussion in 'Public General Chat' started by Rubius, Jan 21, 2011.

  1. Rubius
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    I'm having trouble with these two questions. I already have the answers from Wolfram Alpha, I need to know every step that gets me to the answer.

    1) Sin3X - Sin7X = √(3)sin2X

    [​IMG]

    2) (SinX - CosX)² + TanX = 2sin²X

    [​IMG]

    Solve for X. These questions might look innocent, but they're not. :p
     
    Last edited: Jan 21, 2011
  2. Doc
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    In the first one your taking the square root of the (3)sinx right? And are those already solved, or is that the whole equation?
     
    Last edited: Jan 21, 2011
  3. Rubius
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    The √(3) is the coefficient of Sin2X, they're not all under the radical, which is why I put brackets around the 3. so √(3) times Sin2X
     
  4. Doc
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    Ok I'm glad I asked.
     
  5. Rubius
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    That's the whole equation. The answers are the red dots on the graphs I posted.
     
  6. XStunnaX
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    Dam I remember that stuff so so long ago.
     
  7. TheEPIC
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    [​IMG]
     
  8. Ben K
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    Never got to trigonometric equations. Hopefully I won't need to!
     
  9. Deadend
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    Brain sploded
     
  10. Rubius
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    Just got the first one. YAY!! :D
     
  11. Sirius
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    I did trigonometric equations, but it's been something like seven years and I've forgotten the identities through disuse now... :(
     
  12. Saffaya
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    Way too late in the evening for me to do this, but it isn't a case of identities.

    More of function study since we want the points on the graph, not an equality true for every x.

    find x / f(x) = g(x)
    <=> f(x)-g(x) = 0
    Study the function, it's derivative, it's second derivative and when it is null => the points we want.