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Homework Help: Trigonometric Equation problem

  1. Jul 13, 2010 #1
    I'm stuck on a question from my calculus homework...T_T
    Here's the question...
    There is a large clock at the front of the lounge on the paddle steamer. The hour hand is 28 cm long and takes 12 hours to rotate once. At 2 o'clock the tip of the hour hand is 195 cm above the floor.

    There's no equation given instead there's an image... (please view attachment for the image given)

    The question is write a trigonometric equation that will model the height of the top of the hour hand above the floor. Where h = the height above the floor in centimetres, t = time since 12 O'clock in hours and the angel is measured in radians.

    What I do know is that it must either be a cos or sin graph...
    So must be in the form of h=A sinB(t+c)+D or h=A cosB (t+C)+D

    I think the period is 12 hours...therefore if it is 12 hours the frequency must be pi divided by 6.

    I don't understand how to work out the rest though...

    please help?

    Attached Files:

    • pic.bmp
      File size:
      74.1 KB
  2. jcsd
  3. Jul 13, 2010 #2

    Char. Limit

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    Gold Member

    Well, take what you know and apply it. First, you need to figure out how high the hand is at 3 o clock. That will give you the average height of the graph... and then work from there. I suggest first drawing a few triangles of what you know.
  4. Jul 13, 2010 #3
    At 3 O'clock?? I don't understand
  5. Jul 13, 2010 #4
    It's okay now ^^
    I understand the question now :P
    the equation is h=28sin(pi/6)t +170.8
    got help from a friend xD
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