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Homework Help: How to scale a logistic equation to become dimensionless?

  1. Sep 16, 2014 #1
    1. The problem statement, all variables and given/known data

    I have an equation: dN/dt = N(r-a(N-b)^2) where r,a,b>0 are constants and I need to scale it to the dimensionless form dn/dtao=n(1-a(n-1)^2), however, I tried many ways and I am still unable to get it into the form. The question also suggests using n=N/c and tao=t/d as a substitution.

    2. Relevant equations

    3. The attempt at a solution
    I tried to first expand out the N in the original equation and tried a separation of equation form to get the N's all on one side and dt on the other, but I can't seem to do this. I've also tried to substitute the suggested substitutions, however I can't seem to get it to the form either... :(
  2. jcsd
  3. Sep 16, 2014 #2


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    2017 Award

    Staff: Mentor

    Please show your work then. The given substitutions will work, you just have to find c and d (that will become clear once you simplify the equation).
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