Results 1 to 4 of 4

Math Help - differentiation

  1. #1
    Newbie
    Joined
    May 2011
    Posts
    2

    Post differentiation

    Hello everybody,

    I am new on this forum and I really really need your help hope that i did post my problem in the good forum.

    I am doing a master in transport and I have this exercice to do:

    one a one-way carriageway, the relation between space mean speed Vs (km/h) and density k (veh/km) is: Vs=v0exp(-k/km), where v0=100km/h.

    The relation between flow q and density k is q=kv for heterogeneous traffic and q=k.Vs for heterogeneous traffic, so q=k.v0exp(-k/km).

    I have to find by differentiation k but I am lost. I tried everything but cannot find k. k is suppose to be equal to 50.

    Could you help or guide me a bit.

    Thanks
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member HappyJoe's Avatar
    Joined
    Sep 2010
    From
    Denmark
    Posts
    234
    It is not entirely clear what you wish to do.

    I don't know the physics behind the question in detail, but I know how to differentiate. When you say that you want to find k by differentiation, I suppose you want to find a value of k that makes some function maximal or minimal? And a second question, exactly which of the given functions do you wish to differentiate?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    May 2011
    Posts
    2

    differentiation

    I want to differentiate all that equation with the values I gave above:
    q=k.v0exp(-k/km). v0= 100 and km=50.

    Hope it is clear now.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    -1
    e^(i*pi)'s Avatar
    Joined
    Feb 2009
    From
    West Midlands, England
    Posts
    3,053
    Thanks
    1
    To differentiate with respect to k then use the product rule with u=kv_0 and v = e^{-k/k_m} (chain rule)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 2
    Last Post: July 26th 2010, 06:24 PM
  2. Differentiation and partial differentiation
    Posted in the Calculus Forum
    Replies: 2
    Last Post: May 30th 2010, 11:16 PM
  3. Differentiation
    Posted in the Calculus Forum
    Replies: 2
    Last Post: February 16th 2010, 12:18 PM
  4. differentiation
    Posted in the Calculus Forum
    Replies: 12
    Last Post: February 9th 2010, 11:55 PM
  5. Differentiation and Implicit Differentiation
    Posted in the Calculus Forum
    Replies: 1
    Last Post: February 6th 2009, 05:07 AM

Search Tags


/mathhelpforum @mathhelpforum