1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Critical points.

  1. Mar 17, 2008 #1
    I have to find the critical points for the partials:

    f_x = y/3(24 - 12x - 4y) = 0
    f_y = x/3(24 - 6x - 8y) = 0

    I get y = 0 and x = (6-y)/3 for x in the first partial. How am I supposed to proceed? If I plug these into the secon, it gets nasty. Can anyone demonstrate how this is done?

    Thank you.
     
  2. jcsd
  3. Mar 17, 2008 #2

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    First, you mean, e.g. f_x=(y/3)(24-12x-4y). Put enough parentheses in to make it unambiguous. Second, you don't get y=0 AND x=(6-y)/3, you get y=0 OR x=(6-y)/3. Plug each possibility into the second equation. Third, it doesn't get 'nasty'. You get quadratic equations for x or y. That's not considered 'nasty'.
     
  4. Mar 17, 2008 #3
    That is some gruesome math man.
     
  5. Mar 17, 2008 #4

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    Quadratics?? Are you serious?
     
  6. Mar 17, 2008 #5
    LOL, you just made my night :)
     
  7. Mar 17, 2008 #6

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    Well, thanks. I am trying for the comedian of the year award. Aren't you the artist formerly known as rocophysics? Why the name change?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Critical points.
  1. Critical Points (Replies: 3)

  2. Critical Points (Replies: 12)

  3. Critical Points (Replies: 3)

  4. Critical points (Replies: 4)

Loading...