How to solve y/x if y = x + a in matlab ?

Hello all,

How can you derive y/x in terms of 'a' if y = x + a in matlab? Which commands are needed for that?

Thank you.

[Azzi Abdelmalek]

What do you mean: derive y/x in terms of a?

[Cagdas]

yes im sorry i edited it.

[Image Analyst]

Yes, but it's still not a well explained question. If my answer below doesn't explain it then please see http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer and try to explain it better. Otherwise we'll just say y/x = (x+a)/x, which I don't think is all that useful or interesting.

Answer 1

[Image Analyst]

y/x is used for linear regressions. To do a linear regression, you need to make a "tall" matrix with all the x and y values listed:

y1 = m * x1 + a
y2 = m * x2 + a
y3 = m * x3 + a
y4 = m * x4 + a
y5 = m * x5 + a
y6 = m * x6 + a

etc. This gives y = x * coeffs where

y = [y1;y2;y3;y4;y5;y6] 
x = [
x1, 1;
x2, 1;
x3, 1;
x4, 1;
x5, 1;
x6, 1];

then coeffs = y/x and m = coeffs(1) and a = coeffs(2). Standard least squares formula but in a more compact MATLAB-ish way.