How can i plot the basic fitting line through the origin (0,0)?

Information entered to the command window:

>> x=0:1.96:19.62; y=[0,1,3,11,25,38,52,66,78,93,106];

>> plot(x,y,'+')

>> xlabel('Load/N'); ylabel('Deflection/mm'); title('Measuring the Stiffness of the Spring');

The Figure plotted using the basic fitting linear option:

However I want my best fit line to go through the origin (0,0) without altering the data values or the scale of the axis.

Answer 1

[Are Mjaavatten]

You want to find the slope a of the line

that best fits your data. The least squares solution is to find the a that minimizes

In Matlab you can use the backslash operator to do this, after transposing your arrays to column vectors:

a = x'\y';
plot(x,y,'*',x,a*x)

See also the function polyfix in the Mathworks File Exchange.