Results 1 to 4 of 4

Thread: Could I have some help with this maths?

  1. #1
    Newbie
    Joined
    May 2017
    From
    Syd
    Posts
    1

    Could I have some help with this maths?

    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    16,191
    Thanks
    3686

    Re: Could I have some help with this maths?

    (a) 15 people per hr

    (b). let the rate that people enter be

    $r=220te^{-0.4t}+15$

    use the product rule to determine the derivative of the rate, and set equal to zero to determine critical value(s) of $t$ ...

    $r'(t)=220e^{-0.4t}(-0.4t +1) = 0 \implies t=2.5$

    So, how would you justify $r(2.5)$ is a maximum?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor

    Joined
    Apr 2005
    Posts
    19,454
    Thanks
    2892

    Re: Could I have some help with this maths?

    What happened to the original post? Did "DonkeyyourKong" erase it? That makes non-sense of skeeter's response and makes me, at least, unlikely to help "DonkeyyourKong" on any future post.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    16,191
    Thanks
    3686

    Re: Could I have some help with this maths?

    well, it showed back up ...

    The problem gave a rate that people enter a festival as

    $\dfrac{dE}{dt}=220te^{-0.4t}+15$, $0 \le t \le 12$, where $t=0$ is noon.

    part (a) asked for the rate of entrance at $t = 0$

    part (b) asked for the time when the rate of entrance is a maximum.
    Last edited by skeeter; May 31st 2017 at 07:50 AM.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. O Level maths needs Degree maths Knowledge
    Posted in the New Users Forum
    Replies: 5
    Last Post: May 20th 2012, 08:15 AM
  2. Should I buy maths books to teach myself maths.
    Posted in the Math Topics Forum
    Replies: 2
    Last Post: Nov 21st 2011, 04:45 PM
  3. Help me with my grade 11 maths [easy maths]
    Posted in the Pre-Calculus Forum
    Replies: 11
    Last Post: Dec 27th 2009, 04:09 PM
  4. Replies: 0
    Last Post: Sep 5th 2007, 03:50 AM
  5. Replies: 1
    Last Post: Oct 3rd 2006, 09:59 AM

/mathhelpforum @mathhelpforum