MATLAB Examples

Line Plots

To create two-dimensional line plots, use the plot function. For example, plot the value of the sine function from 0 to $2\pi$:

x = 0:pi/100:2*pi;
y = sin(x);
plot(x,y)

You can label the axes and add a title.

xlabel('x')
ylabel('sin(x)')
title('Plot of the Sine Function')

By adding a third input argument to the plot function, you can plot the same variables using a red dashed line.

plot(x,y,'r--')

The 'r--' string is a line specification. Each specification can include characters for the line color, style, and marker. A marker is a symbol that appears at each plotted data point, such as a +, o, or *. For example, 'g:*' requests a dotted green line with * markers.

Notice that the titles and labels that you defined for the first plot are no longer in the current figure window. By default, MATLAB® clears the figure each time you call a plotting function, resetting the axes and other elements to prepare the new plot.

To add plots to an existing figure, use hold.

x = 0:pi/100:2*pi;
y = sin(x);
plot(x,y)

hold on

y2 = cos(x);
plot(x,y2,':')
legend('sin','cos')

Until you use hold off or close the window, all plots appear in the current figure window.