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    Given that a=pi+qj and has magnitude 10 and makes an angle theta with the positive x-axis where sin theta = 3/5. Find the possible values of p and q.

    Why is p allowed to be negative yet q isn't??
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    (Original post by dont know it)
    Given that a=pi+qj and has magnitude 10 and makes an angle theta with the positive x-axis where sin theta = 3/5. Find the possible values of p and q.

    Why is p allowed to be negative yet q isn't??
    Because \sin \theta is +ve so the angle is between \mathbf{a} and the +ve x-axis is anywhere between 0 and 180 degrees. This is precisely any point on the region y>0.

    Or differently to think about it, 10\sin \theta = q and since \sin \theta is +ve, q must be +ve.
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    (Original post by RDKGames)
    Because \sin \theta is +ve so the angle is between \mathbf{a} and the +ve x-axis is anywhere between 0 and 180 degrees. This is precisely any point on the region y>0.

    Or differently to think about it, 10\sin \theta = q and since \sin \theta is +ve, q must be +ve.
    Thanks, but may I ask what does the positive x-axis mean?
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    (Original post by dont know it)
    Thanks, but may I ask what does the positive x-axis mean?
    The positive portion of the x-axis. So the line x>0
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    (Original post by RDKGames)
    The positive portion of the x-axis. So the line x>0
    But then how can p=-6 as well as 6? If it's -6 doesn't that mean x<0?
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    (Original post by dont know it)
    But then how can p=-6 as well as 6? If it's -6 doesn't that mean x<0?
    The angle is measured from the +ve x-axis, it says nothing about the actual values being on the right side of the y-axis.
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    (Original post by RDKGames)
    The angle is measured from the +ve x-axis, it says nothing about the actual values being on the right side of the y-axis.
    Oh right I see. Thank you.
 
 
 
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