Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

For example, the data points are:

(1,1)

(2,1/2)

(3,1/3)

(4,1/4)

(5,1/5)

How do I find the equation from those points? Do I look at the common ratio of the y-values or something?

share|improve this question
1  
You might note a mapping of the for $x \mapsto 1/x$, right? –  Pedro Tamaroff May 30 '12 at 2:38
    
If it is stated that the datapoints are necesarily that of a rational function of the form $$y=\frac{a}{x+b}+c$$ you can always find $a$, $b$, and $c$ with $3$ entries, by producing a system of equations of 3 variables and 3 equations. –  Pedro Tamaroff May 30 '12 at 2:40
add comment

1 Answer

Since you're just asking for a curve fitting those points, note that each given point $(x,y)$ has the form $\left(x,\frac{1}{x}\right) \Rightarrow y=\frac{1}{x}$. For this particular problem, the problem-solving skill you're using is called pattern recognition.

For other problems that ask you to find the curve given a set number of points, you generally need $n+1$ points to determine an equation with degree $n$. If a pattern isn't immediately evident, then you generally need computer software to find the best fit equation.

share|improve this answer
    
OK, I get it now. –  manaraka May 30 '12 at 20:32
    
Glad it helped! There should be a check mark on the left side that you can click to accept the answer if this has addressed all your questions. –  chris May 30 '12 at 20:34
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.