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Homework Help: Exact Values

  1. Feb 13, 2007 #1
    How can I go about finding the exact values of tan 510, sin (-315) and sin 750? I'm unsure of where to even begin on these problems and any help would be greatly appreciated.


    Never mind, I found the answers to these problems. However, there is another problem on my homework the reads: "Find 2 values of [tex]\theta[/tex] such that 0 degrees < [tex]\theta[/tex] < 360 degrees and sin [tex]\theta[/tex] = -[tex]\sqrt{3/2}[/tex]." I don't have a unit circle handy, so I'm unsure about how to solve it.
     
    Last edited: Feb 13, 2007
  2. jcsd
  3. Feb 14, 2007 #2
    Sin is the y value so on a unit circle and why is negitive in quadrants 3 and 4. so at 240 deg and 300deg it should be that value.
     
  4. Feb 14, 2007 #3

    HallsofIvy

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    tan(x) is periodic with period [itex]\pi[/itex] so surely it would help to note that 510= 2(180)+ 150= 3(180)- 30. Do you know sine and cosine of -30 degrees? -315= 2(180)- 45, and 750= 4(180)+ 30.

    As for your second problem, did it say [itex]-\sqrt{3/2}[/itex] or [itex]-\frac{\sqrt{3}}{2}[/itex]? That's an important difference!
     
  5. Feb 14, 2007 #4
    You're right, I just realized my mistake. It should have said "[itex]-\frac{\sqrt{3}}{2}[/itex]."
     
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