How do I name the trendline in the legend? Also, how can I get the trend line equation on the plot?

Answer 1

[Bjorn Gustavsson]

Maybe:

if c(2) > 0
  equation_string = sprintf('%4.3f x + %4.3f',c(1),c(2));
elseif c(2) < 0
  equation_string = sprintf('%4.3f x - %4.3f',c(1),abs(c(2)));
else
  equation_string = sprintf('%4.3f x',c(1));
end
legend('Data',['Best linear fit: ',equation_string])
text(12,43,equation_string)

HTH

Answer 2

[Star Strider]

It is not possible to run an image of your code.

Try this:

Voltage = linspace(10.45, -1.4, 8);
GaugePressure = linspace(3353, 0, 8);

c = polyfit(Voltage, GaugePressure, 1);
y_est = polyval(c, Voltage);

figure
plot(Voltage, GaugePressure, '--bs')
hold on
plot(Voltage, y_est, 'r--')
hold off
legend('Data', 'TrendLine', 'Location','best')

Add your title and axis label calls.