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Should be a really easy solve - Trap rule using table?

  1. Nov 9, 2009 #1
    Ok so i just have a table of numbers and i need to use the trapezoidal rule to determine the answer of how many water bottles will be filled over the 5 hours.

    n = 5

    Time Rate (bottles/hr)
    8 am 120
    9 am 110
    10 am 115
    11 am 115
    12 pm 119

    Ok i used the equation: h/2 (y + 2y1 + 2y1...+yn) and got:

    (12 - 8)/5 [8 + 2(9) + 2(10) + 2(11) + 12]


    and got 64. So 64 bottles over 5 hours?
     
  2. jcsd
  3. Nov 10, 2009 #2

    Mark44

    Staff: Mentor

    Does your answer make any sense to you? It doesn't to me. You have a machine that can fill somewhere between 110 and 120 bottles per hour, and it's operating for 4 hours, so it ought to be able to fill somewhere between 440 and 480 bottles in that time.

    The step size h is 1 hour, so h/2 = ?
    The function values are the number of bottles filled/hour, not the time.
     
  4. Nov 10, 2009 #3

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    8, 9, 10, 11, 12 are the hours! They are the xn values, not yn!
     
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