Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: How to find the f(x) (least square method)

  1. Dec 6, 2011 #1
    Hi my first post , I hope I chose the right forum?

    I'm here looking for a memory jog not for someone to do my work, I'm trying to remember how to find the f(x) to complete this chart , there is many more data points but I'm just providing you with the top line , I shall do the rest myself, can someone help me please?
    It's been many years since I attempted this problem :(


    x y x^2 xy f(x) f(x)-y (f(x)-y)^2
    ________________________________________________
    -8 6.8 64 -54.4 ?
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Dec 6, 2011 #2
    sorry

    the format is all messed up

    here

    x___y___x^2___x.y____f(x)
    -8__6.8__64____-54.4__?


    sorry for the format but this is the best I can do

    x= -8
    y= 6.8
    x^2 = 64
    x.y = -54.4
    f(x) = ?
     
  4. Dec 6, 2011 #3

    HallsofIvy

    User Avatar
    Science Advisor

    It still is not at all clear what you are asking. Yes, if x= -8 and y= 6.8, then [itex]x^2= 64[/itex] and [itex]xy= -54.4[/itex] but that has nothing to do with some function, "f". Do you have any other information?
     
  5. Dec 7, 2011 #4

    NascentOxygen

    User Avatar

    Staff: Mentor

    A google search on method of least squares will find some good examples for you to follow, if I have you right. Here is one that may help.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook