Results 1 to 8 of 8

Math Help - Finding the minimum product of two numbers whose difference is 8, HOW?

  1. #1
    Junior Member
    Joined
    Oct 2010
    Posts
    27

    Finding the minimum product of two numbers whose difference is 8, HOW?

    Finding the minimum product of two numbers whose difference is 8, HOW?

    This is the solution in my textbook:

    "The quantity to be minimized is the product, p, of two numbers.
    Let one number be n.
    Since the difference between the two numbers is 8, the other number can be represented by n-8 or n+8.
    Either expression can be used. We will use n-8.
    p = n * (n-8)
    ...
    "

    Now the thing I don't get is that why do we need P? Why do we multiply the two numbers?
    Last edited by mr fantastic; October 31st 2010 at 06:04 PM. Reason: Copying title into main body of post.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,621
    Thanks
    426
    Quote Originally Posted by Sorena View Post
    This is the solution in my textbook:

    "The quantity to be minimized is the product, p, of two numbers.
    Let one number be n.
    Since the difference between the two numbers is 8, the other number can be represented by n-8 or n+8.
    Either expression can be used. We will use n-8.
    p = n * (n-8)
    ...
    "

    Now the thing I don't get is that why do we need P? Why do we multiply the two numbers?
    what is the definition of the word "product"?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor

    Joined
    Apr 2005
    Posts
    15,368
    Thanks
    1313
    Quote Originally Posted by skeeter View Post
    what is the definition of the word "product"?
    You may find it hard to believe, skeeter, but I have had classes full of college students who would have trouble answering your question. To them a "product" is something advertised on TV and has nothing to do with mathematics!
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Junior Member
    Joined
    Oct 2010
    Posts
    27
    ok, so what does it mean?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member
    Joined
    Oct 2010
    Posts
    27
    well i kinda know it means the multiple of the 2 numbers, the thing I don't understand is that why we need to get that? how does that help?
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by Sorena View Post
    well i kinda know it means the multiple of the 2 numbers, the thing I don't understand is that why we need to get that? how does that help?
    The question was
    Finding the minimum product of two numbers whose difference is 8
    Given the question, I don't understand why you would not understand the importance of getting the product!
    Follow Math Help Forum on Facebook and Google+

  7. #7
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,621
    Thanks
    426
    Quote Originally Posted by Sorena View Post
    well i kinda know it means the multiple of the 2 numbers, the thing I don't understand is that why we need to get that? how does that help?
    the problem wants you to find the minimum product of two numbers whose difference is 8

    the product of two numbers is the result when you multiply the two numbers ...

    the product = (first number) times (the second number)

    P = n(n-8)

    note that the graph of P = n(n-8) is a parabola ... the vertex of the parabola is the location of the minimum product.

    what do you know about finding the vertex of a parabolic graph?
    Follow Math Help Forum on Facebook and Google+

  8. #8
    Junior Member
    Joined
    Oct 2010
    Posts
    27
    LOL, I didn't even read the question properly, their difference was in my mind, thanks for the help though.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 3
    Last Post: November 14th 2010, 07:51 PM
  2. Difference and Minimum
    Posted in the Calculus Forum
    Replies: 1
    Last Post: May 18th 2010, 02:11 PM
  3. Replies: 0
    Last Post: September 15th 2009, 09:27 PM
  4. Replies: 5
    Last Post: March 3rd 2008, 07:42 PM
  5. Minimum Significance Difference
    Posted in the Advanced Statistics Forum
    Replies: 0
    Last Post: January 26th 2007, 06:11 AM

Search Tags


/mathhelpforum @mathhelpforum