Results 1 to 4 of 4

Math Help - optimization - distence/intensity of lamps

  1. #1
    Junior Member
    Joined
    Oct 2009
    Posts
    68

    optimization - distence/intensity of lamps

    Two lamps are of intensities 40 and 5 candle-power respectively and are 6m apart. If the intensity of the illumination I, at any point is directly proportional to the power of the source and inversely proportional to the square of the distance from the source, find the darkest point on the line joining the two lamps.

    im not sure how to work with the proportions.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member
    Joined
    Nov 2009
    Posts
    277
    Thanks
    2

    Is this a straight line problem?

    The 2 distances seem to be x and 6-x. Then the intensity would be:

    <br />
I = \frac{40}{x^2} + \frac{5}{(6-x)^2}<br />
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Oct 2009
    Posts
    68
    this is the equation i found as well ...but i cant seem to get the correct answer.

    im supposed to find the derivative and equate to zero right?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Senior Member
    Joined
    Nov 2009
    Posts
    277
    Thanks
    2

    I agree

    yes
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Distence bewteen a pt. and plane
    Posted in the Calculus Forum
    Replies: 10
    Last Post: March 18th 2011, 11:16 AM
  2. intensity of beam of light
    Posted in the Calculus Forum
    Replies: 4
    Last Post: April 9th 2010, 10:00 PM
  3. Sound Intensity Problem
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: November 13th 2009, 12:05 PM
  4. Sound Intensity Problem
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: May 20th 2009, 03:02 PM
  5. function of intensity
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: August 24th 2008, 10:31 AM

Search Tags


/mathhelpforum @mathhelpforum