Results 1 to 3 of 3

Thread: Related rates problem

  1. November 19th 2010, 07:05 AM #1
    softballchick
    softballchick is offline
    Junior Member
    Joined
    Jul 2010
    Posts
    59

    Related rates problem

    Let be the area of a circle with radius . If , find when .
    Thanks


    Moderator edit: Deleted post restored. Thread closed.
    Last edited by mr fantastic; November 19th 2010 at 08:01 PM. Reason: Restored deleted question.
    Follow Math Help Forum on Facebook and Google+
  2. November 19th 2010, 07:12 AM #2
    Unknown008
    Unknown008 is offline
    MHF Contributor Unknown008's Avatar
    Joined
    May 2010
    From
    Mauritius
    Posts
    1,260
    \dfrac{dA}{dt} = \dfrac{dA}{dr} \times \dfrac{dr}{dt}

    You know dr/dt.

    You know that A = \pi r^2

    Find dA/dr and plug in r = 1 and plug that in the chain rule equation.
    Follow Math Help Forum on Facebook and Google+
  3. November 19th 2010, 07:12 AM #3
    harish21
    harish21 is offline
    MHF Contributor harish21's Avatar
    Joined
    Feb 2010
    From
    Dirty South
    Posts
    1,036
    Thanks
    10
    A=\pi\;r^2

    \dfrac{dA}{dt} = 2\pi r \; \dfrac{dr}{dt}
    Follow Math Help Forum on Facebook and Google+
« Find potential Function | Compute f'(x) and finding critical numbers »

Similar Math Help Forum Discussions

  1. Related Rates Problem
    Posted in the Calculus Forum
    Replies: 1
    Last Post: October 17th 2011, 08:30 PM
  2. Related Rates Problem
    Posted in the Calculus Forum
    Replies: 2
    Last Post: January 17th 2011, 09:06 PM
  3. Related Rates problem
    Posted in the Calculus Forum
    Replies: 1
    Last Post: March 1st 2010, 10:39 AM
  4. related rates problem
    Posted in the Calculus Forum
    Replies: 1
    Last Post: February 25th 2010, 01:34 PM
  5. Related rates problem
    Posted in the Calculus Forum
    Replies: 1
    Last Post: October 3rd 2009, 02:42 PM

Search Tags


/mathhelpforum @mathhelpforum