How to solve polyfit(x,y,1) by hand?

Hello so I know how to find polyfit using matlab but how do I find it without matlab? I need to know how to do it for linear equations like polyfit(x,y,1) can we assume that x=[1 2] and y=[3 4] and thanks alot I appreciate the help

Answer 1

[John D'Errico]

To solve it without MATLAB, just read ANY of hundreds of books or websites about linear regression modeling.

Start here:

https://en.wikipedia.org/wiki/Linear_regression

[Husain Alshati]

I tried that but couldn't find anything could you explain how polyfit works?

[Guillaume]

I tried that but couldn't find anything

You're kidding, right? There are zillions of books dedicated to linear regressions. The wikipedia article that John linked also explains it all.

In addition you can even look at the code of polyfit and see for yourself exactly how it does it.

[Husain Alshati]

Then maybe you could find something from these zillions of books because I could not.

Answer 2

[Torsten]

If you only have two points for a polynomial of degree 1, you have to solve a linear system of two equations:

3 = a*1 + b
4 = a*2 + b

for a and b.

The equation of the line is then given by

y = a*x + b

Best wishes

Torsten.