Results 1 to 5 of 5

Math Help - Questions about Optimization Problems

  1. #1
    Junior Member
    Joined
    Jun 2007
    Posts
    26

    Questions about Optimization Problems

    1. An open box is to be made from a 3x4 piece of paper by cutting equal squares from each corner. Find the volume of the largest box.

    Question: Okay, this is ridiculous, but if my x-value turns out (7+/-√31) / 6, how do I know which value to use?

    2. A paper contains 45 square inches of print. The margins at top/bottom are 1.5 in. At each side, they are 1 in. What are the dimensions in order to have a minimum amount of paper?

    The answer's √30 x (3√30)/2, but I'm not getting the same answer.

    3. Find the point on the graph of y=x^3 closest to the point (2,0).

    Question: Do I just use the distance formula for this?

    Any help is greatly appreciated.

    Thanks!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Aug 2007
    From
    USA
    Posts
    3,110
    Thanks
    2
    Quote Originally Posted by alreadyinuse View Post
    how do I know which value to use?
    Domain!!

    It makes no sense to cut out a square with NEGATIVE sides, so x > 0.

    If you have a 3" side, you cannot cut squares more that 1.5" (Why?), so 0" < x < 1.5".

    Which, if any, of your possible solutions is in that Domain?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Jun 2007
    Posts
    26
    Wow, I feel like an idiot.

    Haha, thank you for your help!
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Super Member angel.white's Avatar
    Joined
    Oct 2007
    Posts
    723
    Awards
    1
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor
    Joined
    Aug 2007
    From
    USA
    Posts
    3,110
    Thanks
    2
    Quote Originally Posted by alreadyinuse View Post
    Wow, I feel like an idiot.
    No need for that.

    It is often overlooked in the teaching presentation, the very important step: "Sit back. Relax. Think about it for a moment. Ask yourself if it all makes sense."

    Now you know.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Optimization questions
    Posted in the Calculus Forum
    Replies: 3
    Last Post: May 28th 2010, 02:52 AM
  2. Optimization questions
    Posted in the Calculus Forum
    Replies: 3
    Last Post: December 14th 2009, 06:38 PM
  3. Urgent Optimization Questions
    Posted in the Calculus Forum
    Replies: 4
    Last Post: November 17th 2009, 03:50 PM
  4. Optimization and vector questions
    Posted in the Calculus Forum
    Replies: 1
    Last Post: August 30th 2009, 05:28 PM
  5. optimization questions
    Posted in the Math Topics Forum
    Replies: 1
    Last Post: April 22nd 2008, 08:31 PM

Search Tags


/mathhelpforum @mathhelpforum