estimate the parameters of an equation
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    Nikolas Spiliopoulos
 on 20 Mar 2017
  
    
    
    
    
    Answered: Steven Lord
    
      
 on 20 Mar 2017
            Hi there,
I have a question:
I have an equation like this: 45=a*5^b;
is there any way to estimate a and b only from this equation?
thanks
1 Comment
  Adam
      
      
 on 20 Mar 2017
				At a glance, without putting much thought into it I'd imagine there are an infinite number of solutions unless you are restricting yourself to integers only.
Accepted Answer
  Star Strider
      
      
 on 20 Mar 2017
        No.
You are estimating 2 parameters with 1 (x,y) data pair. There is no unique solution.
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More Answers (1)
  Steven Lord
    
      
 on 20 Mar 2017
        Borrowing a problem from Cleve: "I'm thinking of two numbers. Their average is 3. What are the numbers?" I just wrote down my answer; I would be very surprised if you gave the same answer I wrote down.
Like Cleve's question, your question has infinitely many solutions. But if you want the solution for a in terms of b:
syms a b
f = 45 == a*5^b;
asol = solve(f, a)
check = isAlways(subs(f, a, asol))
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