Results 1 to 2 of 2

Math Help - Finding a maximum height. (Polynomial function)

  1. #1
    Newbie
    Joined
    Mar 2011
    Posts
    1

    Finding a maximum height. (Polynomial function)

    Hi, I have the correct answer but I am not sure how I got it:

    The path of a diver is given by

    y= -4/9x^2 + 24/9x + 12 where y is the height (in feet) and x is the horizontal distance from the end of the diving board (in feet). What is the maximum height of the diver?

    Ok, so I used this formula : -b/2a (the vertex) to get x = 3. Apparently that is the answer, but I'm curious as to why they wouldn't plug 3 as the x value to get the height. Any help is appreciated. Thanks.
    Last edited by msinger23; March 7th 2011 at 02:59 PM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    9,663
    Thanks
    298
    Awards
    1
    Quote Originally Posted by msinger23 View Post
    Hi, I have the correct answer but I am not sure how I got it:

    The path of a diver is given by

    y= -4/9x^2 + 24/9x + 12 where y is the height (in feet) and x is the horizontal distance from the end of the diving board (in feet). What is the maximum height of the diver?

    Ok, so I used this formula : -b/2a (the vertex) to get x = 3. Apparently that is the answer, but I'm curious as to why they wouldn't plug 3 as the x value to get the height. Any help is appreciated. Thanks.
    The problem statement is asking for the maximum height, so you are correct in saying we need to find y(3). Beware though that many problems like this only ask for where the max height is. In this case it looks like a typo on the book's part as it seems they only want the location (x = 3) and not the actual height y(3) that they are actually asking for.

    -Dan
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 3
    Last Post: October 15th 2011, 06:21 AM
  2. what is the maximum height...
    Posted in the Calculus Forum
    Replies: 2
    Last Post: October 11th 2011, 07:40 AM
  3. Replies: 12
    Last Post: May 20th 2011, 11:56 AM
  4. Velocity and maximum height
    Posted in the Calculus Forum
    Replies: 3
    Last Post: April 30th 2009, 12:26 PM
  5. Replies: 0
    Last Post: November 19th 2007, 12:51 AM

Search Tags


/mathhelpforum @mathhelpforum