Thread: Non-Linear Least Square

Hi guys,

I've been presented with a maths puzzle/equation to solve, but after some searching and an attempt at a self taught crash course I've still not been able to find a solution to this problem. So could anyone solve this please.

I need to find the approx values of a-f in this equation.

y = ax^5 - bx^4 + cx^3 - dx^2 + ex - f

Where x and y are....

x y
-15 -5,439,067
-10 -726,897
-5 -24,127
5 21,213
10 685,283
15 5,232953

If anyone could solve this that would be great thanyou.

Barry

You can solve this system of linear equations using WolframAlpha

Hi thanks for the link, but unless I'm missing something (and I literally have no idea at all) but I don't think that could work out non linear regression equations (not that I know exactly what that means but I think I get the gist). There's no-where to put parameters in. Or am I wrong?

Originally Posted by Baz300

Hi thanks for the link, but unless I'm missing something (and I literally have no idea at all) but I don't think that could work out non linear regression equations (not that I know exactly what that means but I think I get the gist). There's no-where to put parameters in. Or am I wrong?

If you plug in values of x and y into starting equation you should obtain six equations with six unknowns (a,b,c,d,e,f)

Do you mean input the equation 6 times each with the different set of x and y values. I tried with one set and obviously it spouted out the equation back at me in a few different ways but no values for a to f.

Thanks Barry

Originally Posted by Baz300

Do you mean input the equation 6 times each with the different set of x and y values. I tried with one set and obviously it spouted out the equation back at me in a few different ways but no values for a to f.

Thanks Barry

I don't know how you did that but that's great, thanks so much for your time and patience.

Regards, Barry