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!

Optimization of y=x^2 towards (2,1)

  1. May 12, 2012 #1
    Hi! Probably quite easy for you guys (Im not even sure im in the right thread).

    The assignment is in constrained optimization, and we're supposed to use lagrange to find the point on the parabola y=x^2 which is closes to (2, 1). I've been trying for a while and cant seem to find the right answer, so I hope you can help me.

    Cheers!

    Updated: Im putting in my "progress":

    I've used lagrange, with the restriction (y-x^2), and objective function (x-2)^2 + (y-1)^2
    Cutting the lambda I get:

    2(x-2)=2(y-1)(-2x)

    y-x^2=0

    And from there I dont know where to go. :(
     
    Last edited: May 12, 2012
  2. jcsd
  3. May 12, 2012 #2

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    You're supposed to? You mean this is work for a class? Then it should have been posted in the "homework and classwork" section. I will move it. Also, you are required to show what you have done yourself so we will know what hints you need. Since you say you have "been trying for a while", you should have a lot to show us.
     
  4. May 12, 2012 #3
    Ah, thanks. It is my first post as you see, and its not homework, but it is in a textbook. Im starting math again by myself and its hard when you dont have anyone to ask. (Im working with political sciences;)
     
  5. May 12, 2012 #4
    Just so you know, for the purposes of Physics Forums it doesn't matter whether it's actual homework. As long as it's a homework-style question, you have to do things like show the work you've already done in order to get help.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook