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Homework Help: Using Graph to determine constants in equation

  1. Jan 23, 2012 #1
    Hello,

    i have the equation F= x + kx^n

    I am trying to determine the constants k and n? where i have the ranges for F and x

    is what i am doing correct?

    log F= logx + logk+ nlogx

    log F= logx(1+n) + logk


    ok i would then plot logF vs Log x. if i am correct logk = y intercept and from that k can be calculated. How would i use the gradient to find the value of n. can someone plz give me some assistance. much appreciated.
     
  2. jcsd
  3. Jan 23, 2012 #2

    ehild

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    Homework Helper


    No, it is WRONG... log(a+b) is not equal to log(a )+ log(b)

    But log(F-x)=log(kx^n)= logk+n logx.

    Plot out log(F-x) in terms of logx. It has to be a straight line, with y-intercept logk and slope n.

    ehild
     
    Last edited: Jan 23, 2012
  4. Jan 24, 2012 #3
    thank you very much for that correction!
     
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