Once I've found a custom equation for a scatter plot with the curve fitting tool, how do I apply that line to the scatter plot in live editor?

I have a scatter plot, and have rearranged for the custom equation but I do not know how to apply this equation to my scatter plot on my livescript.

Answer 1

[Pawel Jastrzebski]

IF you're working on a one-off case, use the in-built tools:

Once you're happy with the plot settings, you can always get Matlab to generate the code of the plot for you - this way you can learn how certain things get done and develop your own code, which will be more human-friendly:

But if you're working on a re-usable code, read these:

• Polyfit
• Polyval

And check out the code below:

clear all;
clc;

% DATA
x = 1:20;
y = randn(1,20);

figure
plot(x,y,'bo');
hold on;

% CF - CURVE FITTING DATA 

CFcoeff = polyfit(x,y,1); % coeeficients of the fit | 1 for linear fit

xLimits = xlim; % limits of the  current plot
xCF = linspace(xLimits(1),xLimits(2),50); % xData for the fit line
yCF = polyval(CFcoeff,xCF);

plot(xCF,yCF,'r-');

% ADD EQUATION ANNOTATION TO THE PLOT:
equationText = ['y = ' sprintf('%.2f',CFcoeff(1)) 'x' sprintf('%+.2f',CFcoeff(2))];
text(x(1), yCF(1)+0.2,equationText,...
    'Color','r');