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Homework Help: Trig Equation

  1. Jun 5, 2009 #1
    a) Use the special triangles and the CAST rule to solve the equation 2sinx + [tex]\sqrt{3}[/tex] = 0 for the domain interval 0 [tex]\leq[/tex] x [tex]\geq[/tex] 360.

    b) What feature of the graph, in the form y = asinx + b, would show the solutions?

    My Answers:

    a) sinx = -[tex]\sqrt{3}[/tex]/2
    x = -60 degrees

    180 + 60 = 240 degrees
    360 - 60 = 300 degrees

    b) Can anybody give me a clue as to what this is asking? I have absolutely no idea :(
  2. jcsd
  3. Jun 5, 2009 #2


    Staff: Mentor

    For b, think about where the graph of y = 2sinx + sqrt(3) crosses the x-axis. I think that's what the problem is getting at.
  4. Jun 5, 2009 #3
    This is what I was thinking of as the graph will cross x at 4Pi/3 and 5Pi/3, so I was thinking that the feature to show the solution would be the x-intercepts.

    Is this correct? I originally thought this but then was confused by the words "feature of the graph"
  5. Jun 5, 2009 #4


    Staff: Mentor

    An x-intercept is a feature of a graph. Again, I think this is what the question is getting at.
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