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

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The discussion revolves around using the trapezoidal rule to calculate the total number of water bottles filled over five hours based on a provided rate table. The user initially applied the trapezoidal formula incorrectly, leading to a result of 64 bottles, which seems inconsistent with the expected output based on the hourly rates. Participants point out that the time values (8 am to 12 pm) were mistakenly treated as function values instead of the actual rates of bottle filling. The correct interpretation of the trapezoidal rule requires proper identification of the function values and the step size. Clarification on these points is essential for accurately determining the total number of bottles filled.
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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?
 
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zaboda42 said:
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?

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.
 
zaboda42 said:
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?
8, 9, 10, 11, 12 are the hours! They are the xn values, not yn!
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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