linear equation without coefficients

hello. so i am a beginner in matlab and i would need some help in solving a problem. I have 2 vectors x and y with 10 values each and the equation y=a*x+b. The task is to find the values for a and b. I know how to do this on paper, but i don t know how to code it. Please help.

[Ana Monea]

Now i understand what you were saying. I was a bit confused, but now it s clear. Thank you!

Answer 1

[William Alberg]

I think the polyfit command is what you are looking for. It should work like this

k = polyfit(x,y,1)
a = k(1)
b = k(2)

[Ana Monea]

thank you..i don t really understand if i should put a for also so i could find all the a and b for the 10 values from the vectors or the code that you gave me is the final answer

[William Alberg]

Sorry, i don't follow. do you want to find an "a" and "b" for each set of "x" and "y"?

[Image Analyst]

Explain what "put a for also" means. k is the coefficients and k(1) is the coefficient of x and k(2) is the offset (what you called b). It does a linear regression through your 10 data points.

Explain what you mean when you say "all the a and b". Exactly how many a and b do you think there should be? There are only one a and one b. You need at least 2 points to pass a line through, so no matter if you have 2 points or 2000 points, you'll have only one a and one b.

[Ana Monea]

I understand now what you said thank you. And also on this exercise i have 10 values for x and z vectors and i have to find the c coefficient from z=c*sqrt(x). Can you help me on that too please?

[William Alberg]

I have not tried that before. But it appears that the following code works.

F = @(x,xdata) x(1)*sqrt(xdata);
c = lsqcurvefit(F,0,x,z)

It can end up in a local minimum point, so you should be aware of that