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Homework Help: Trigonometry question

  1. Sep 12, 2009 #1
    1. The problem statement, all variables and given/known data

    Suppose that x=7pi/23 is a solution of the equation sinx= A where A is some constant.
    Then A must be equal to [blank], and the other solution of the equation in the interval [0,2pi] must be x = [blank].

    3. The attempt at a solution

    So I've plugged the value in to my calculator and found A, but I completely forget Trigonometry. How would I go about finding the second solution?

  2. jcsd
  3. Sep 12, 2009 #2
    The identity you need to use is sinx = sin([itex]\pi[/itex] - x). Can you see how this shows the symmetry of sinx in the first and second quadrant where two x values give the same A value?
  4. Sep 12, 2009 #3
    Not really, I can see it in my calculator but I don't completely understand it :P and should I be getting a different value?
  5. Sep 13, 2009 #4


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    Homework Helper

    As Bohrok pointed out when x is a solution so too is pi-x
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