MATLAB: How to get trendline equation for to graphs

plots trendlines equtions

So i have made two plots on the same graph,and now i need trendline equtions for them both. I know how to get the trendlines themselfs and only one equation at a time,but i was wondering if there is a way for them both to be present at the same time? Because if i use tools->basic fitting then only one equation for one plot can be on the graph. Thanks

Best Answer

Calculate the line fit variables in your code using polyfit: http://ch.mathworks.com/help/matlab/ref/polyfit.html

Using the parameters, calculate x and y values for each fit.

After plotting your points, use the command "hold on" to plot the other datapoints and all trendlines.

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MATLAB: Hi.. Do anybody knows, how to fit a custome equation for multiple curves at the same time.

lsqcurvefit can be used to fit N-dimensional curves (for you N=760).

https://www.mathworks.com/matlabcentral/answers/431697-make-curve-fitting-faster#comment_687701

MATLAB: Adding trendline to a plot

I'd fit the portion of the data you're interested in to a line using polyfit. Then use polyval to get the points on the line over the entire range that you're interested in. See this demo:

clc;    % Clear the command window.
workspace;  % Make sure the workspace panel is showing.
format longg;
format compact;
fontSize = 20;
% Define equation.
x = -2:20;
y = (x-2).^2;
% Plot it
plot(x,y, 'bo-', 'LineWidth', 3);
grid on;
title('y = (x-2).^2', 'FontSize', fontSize);
xlabel('X', 'FontSize', fontSize);
ylabel('Y', 'FontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
% Give a name to the title bar.
set(gcf,'name','Demo by ImageAnalyst','numbertitle','off') 
% Fit the range fro 10 to 20 with a line.
limitedRange = 10:20;
coeffs = polyfit(x(limitedRange), y(limitedRange), 1)
% Define the range where we want the line
xFitting = 0:19; % Or wherever...
yFitted = polyval(coeffs, xFitting);
% Plot the fitted line over the specified range.
hold on; % Don't blow away prior plot
plot(xFitting, yFitted, 'ro-', 'LineWidth', 2);
legend('Original Data', 'Line Fit');

Best Answer

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MATLAB: Hi.. Do anybody knows, how to fit a custome equation for multiple curves at the same time.

MATLAB: Adding trendline to a plot

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