Get a function by results I already have

[goral_ehad]

Hello,

I have 2 kinds of values, x and y. Each of them can have values between -150 to 150. I have an unknown function f(x,y)=z.
I have many results, like: f(50,60) = 70, f(10,-10) = 2 etc..
i have many many results for this.
The result z of f(x,y) can be between -100 to 100.
I also have the data that f(100,75) =100 (and any values above), and the same for f(-100,-75) = -100.

I would like to use these many results I have, in order to set some function that for each (x,y) will return the result of f(x,y), or something very close to the real result z.

How can I do it?


Thank you

 

[Deleted member 4993]

Hello,

I have 2 kinds of values, x and y. Each of them can have values between -150 to 150. I have an unknown function f(x,y)=z.
I have many results, like: f(50,60) = 70, f(10,-10) = 2 etc..
i have many many results for this.
The result z of f(x,y) can be between -100 to 100.
I also have the data that f(100,75) =100 (and any values above), and the same for f(-100,-75) = -100.

I would like to use these many results I have, in order to set some function that for each (x,y) will return the result of f(x,y), or something very close to the real result z.

How can I do it?


Thank you

Do you have access to Excel software?

 

[goral_ehad]

Do you have access to Excel software?

yes I do

 

[JeffM]

This is a common problem. You can exactly fit a trig or a polynomial function to any finite set of data. Unfortunately, you have no assurance that that exact function is meaningful. An alternative approach is to graph the data, decide what kind of function it looks like, and use multiple regression to test that hypothesis.