1. Limited time only! Sign up for a free 30min personal 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!

I need help with this homework problem

  1. Oct 14, 2012 #1
    1. The problem statement, all variables and given/known data

    Find three positive numbers whose sum is 12 and the sum of whose squares is as small as possible.

    2. Relevant equations



    3. The attempt at a solution

    I don;t even know how to start this one, this is a section from partial derivatives on the max and mins. Please i need guidance through this exercise. Thank you!
     
  2. jcsd
  3. Oct 14, 2012 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Hi ScienceGeek24! :smile:

    Start by calling the three numbers x y and z, and putting f(x,y,z) = x2 + y2 + z2 :wink:
     
  4. Oct 14, 2012 #3
    In addition to tiny-tim's good first idea, how about using the fact that you know that x+y+z=12, so you know what z is in terms of x and y - then you only have a 2D problem to solve.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: I need help with this homework problem
Loading...