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Homework Help: Pls help with one of 2 questions

  1. Sep 19, 2007 #1
    1. The problem statement, all variables and given/known data

    I have this questions an answer to it would be great.
    .Q.1 At t minutes after an engine starts, the rate of fuel consumption is Rkg per minute. it is given by R=10+ 10/2t+1.

    a) Sketch R as a function of t

    b) find the rate of consumption after 7 mins

    c) find the limiting value of R as t becomes very large

    d) calculate the total consumption in the 1st 7 mins

    not sure how to do it
    Thank You

    2. Relevant equations

    3. The attempt at a solution

    I can do part 2
  2. jcsd
  3. Sep 19, 2007 #2


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    Homework Helper

    Is that rate supposed to be R = 10+ [10/(2t+1)] ? I think it would be for question (c) to have a sensible answer. The question is asking you what the limit of R is as t goes to infinity.

    As for (d), you have a function giving you the *rate* of consumption with time. If you want to know how *much* fuel has been used in the time interval 0 <= t <= 7 minutes, what operation must you perform on the function R(t)?
  4. Sep 19, 2007 #3
    so wat is the function is that R(t)= 10+(10/2t+1)
  5. Sep 19, 2007 #4


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    Yes, that is the fuel consumption rate function.
  6. Sep 19, 2007 #5
    so i no the value will not go >10 or equal to 10 but im not sure how to calculate that
  7. Sep 19, 2007 #6
    i no it wll approach but neva touch 10 if you graphed but as i said not sure on the calculations
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