How to display trendline equation on the plot?

Hi

I got the trendline using polyfit() and polyval(). and use plot() to the plot the trendline.

Now my question is how to display the trendline equation onto the plot? Thanks

here are the code for plotting trendline fittedlinecrossplot=polyfit(xdata_crossplot,ydata_crossplot,trendlinepolynomialcoeff); ydata_crossplot_trendline=polyval(fittedlinecrossplot,xdata_crossplot_trendline); hp=plot(hrightsubplot,xdata_crossplot_trendline,ydata_crossplot_trendline,'--g','linewidth',2,'DisplayName',legendlabel_trendline);

Answer 1

[roudan]

ok, I got it now.

here are my codes,

fittedlinecrossplot=polyfit(xdata_crossplot,ydata_crossplot,trendlinepolynomialcoeff); ydata_crossplot_trendline=polyval(fittedlinecrossplot,xdata_crossplot_trendline);

            trendlineequationcoeffnum=length(fittedlinecrossplot);

            switch trendlineequationcoeffnum
                case 2  % means it has slope and intercep 2 numbers
                     trendlineequationstring=sprintf('y=%.3f x+%.3f',fittedlinecrossplot(1),fittedlinecrossplot(2));
                case 3
                     trendlineequationstring=sprintf('y=%.3f x^2+%.3f x+%.3f',fittedlinecrossplot(1),fittedlinecrossplot(2),fittedlinecrossplot(3));
                case 4
                    trendlineequationstring=sprintf('y=%.3f x^3+%.3f x^2+ %.3f x+%.3f',fittedlinecrossplot(1),fittedlinecrossplot(2),fittedlinecrossplot(3),fittedlinecrossplot(4));
                case 5
                    trendlineequationstring=sprintf('y=%.3f x^4+%.3f x^3+ %.3f x^2+%.3f x+%.3f',fittedlinecrossplot(1),fittedlinecrossplot(2),fittedlinecrossplot(3),fittedlinecrossplot(4),fittedlinecrossplot(5));
            end
            htrendlinetext=text(pos_rightsubplot(1)+0.5*pos_rightsubplot(3),pos_rightsubplot(2)+0.8*pos_rightsubplot(4),trendlineequationstring,'units','normalized');

            htrendlinetext.FontSize=12;
            htrendlinetext.FontWeight='bold';
            htrendlinetext.Color='r';