Display equation of exponential fitted line using fit function

Here's my code, I want to find the equation of the fitted line on either of the figures.

clc
clear

T = readtable('ViscosityResults.xlsx','Range','L2:M14',...                  #read spreadsheet and select range
    'ReadVariableNames',true,'VariableNamingRule','preserve')...            #take headings from file and keep them as they are

figure; %experimental results

    x = T{:,1}
    y = T{:,2}
    f = fit(x,y,'exp1');                                                    %create variables

    plot(f,x,y)
    xlim([0,40])
    ylim([0,40])
    title('Viscosity of ED1242-9001 primer by % volume water','(experimental results)')
    xlabel('% Volume water')
    ylabel('Viscosity (cP)')                                                %plot and format graph
    grid on

figure; %forecast graph
    
    xx=linspace(0,80,500);
    plot(xx,f(xx))
    xlim([0,80])
    ylim([0,40])
    title('Viscosity of ED1242-9001 primer by % volume water')
    xlabel('% Volume water')
    ylabel('Viscosity (cP)')                                                %plot and format graph
    grid on

Answer 1

[Davide Masiello]

See if this works

clc
clear
T = readtable('ViscosityResults.xlsx','Range','L2:M14',...                  #read spreadsheet and select range
    'ReadVariableNames',true,'VariableNamingRule','preserve')...            #take headings from file and keep them as they are
figure; %experimental results
    x = T{:,1}
    y = T{:,2}
    f = fit(x,y,'exp1');                                                    %create variables
    txt = sprintf('f(x)=%.2f*exp(%.2f*x)\n',[f.a,f.b]);
    plot(f,x,y)
    xlim([0,40])
    ylim([0,40])
    title('Viscosity of ED1242-9001 primer by % volume water','(experimental results)')
    xlabel('% Volume water')
    ylabel('Viscosity (cP)')                                                %plot and format graph
    text(min(x),max(y),txt)
    grid on

figure; %forecast graph
    
    xx=linspace(0,80,500);
    plot(xx,f(xx))
    xlim([0,80])
    ylim([0,40])
    title('Viscosity of ED1242-9001 primer by % volume water')
    xlabel('% Volume water')
    ylabel('Viscosity (cP)')                                                %plot and format graph
    text(min(x),max(y),txt)
    grid on

[Daniel Jordan]

Sorry for taking such a long time getting back to you, that works thank you! Is there a way to move where the equation is displayed?

[Walter Roberson]

The equation is currently being displayed according to

    text(min(x),max(y),txt)

so change the min(x) and max(y) to whatever values are appropriate for your purpose.

You might also want to consider instead using legend() to display the equation.

[Davide Masiello]

Yes. The first two entries of the command text() are the coordinates where the top-left corner of the bounding box of the displayed text are placed.

For more info, I suggest you check this link

https://uk.mathworks.com/help/matlab/ref/text.html