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Math Help - Finding the formula for a graph

  1. #1
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    Exclamation Finding the formula for a graph



    I need help with finding the horizontal shift for the function P = f(t). Also how would we find the formula for this? I already know that Midline is 2100, Amplitude is 900. But I don't know how to complete this formula...
    900 * sin (???) + 2100

    Thanks.
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  2. #2
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    The period of this function is 4

    Use the fact that n influences the period in \sin(nx)

    and period is given by \frac{2\pi}{n}

    so solve 4=\frac{2\pi}{n}
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  3. #3
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    Quote Originally Posted by florx View Post

    I need help with finding the horizontal shift for the function P = f(t). Also how would we find the formula for this? I already know that Midline is 2100, Amplitude is 900. But I don't know how to complete this formula...
    900 * sin (???) + 2100

    Thanks.
    P(t) = -900\sin\left[B(t \pm C)\right] + 2100

    B = \frac{2\pi}{4} = \frac{\pi}{2}

    C = phase shift ... looks close to a 0.5 shift to the left to me.
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  4. #4
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    Hmm, I don't get how you got -900 from. The amplitude is 900. What made you put a negative in front of it? Also where did you get the 0.5 from. What formula did you use?
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  5. #5
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    Quote Originally Posted by florx View Post
    Hmm, I don't get how you got -900 from. The amplitude is 900. What made you put a negative in front of it? Also where did you get the 0.5 from. What formula did you use?
    look at the curve ... it's an inverted sine wave.

    amplitude = |A|

    as far as the 0.5 ... no formula, I just looked at the graph's horizontal shift.
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