Line Plots

To create two-dimensional line plots, use theplotfunction. For example, plot the sine function over a linearly spaced vector of values from 0 to $$2\pi$$:

x = linspace (0, 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 theplotfunction, you can plot the same variables using a red dashed line.

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

"r--"is aline specification．每种规范可以包括人物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, usehold on．Until you usehold offor close the window, all plots appear in the current figure window.

x = linspace (0, 2 *pi); y = sin(x); plot(x,y) holdony2 = cos(x); plot(x,y2,":") legend("sin","cos") holdoff

3-D Plots

Three-dimensional plots typically display a surface defined by a function in two variables, $$z=f(x,y)$$．For instance, calculate $$z=x{e}^{-x^2-y^2}$$given row and column vectorsxandywith 20 points each in the range [-2,2].

x = linspace(-2,2,20); y = x'; z = x .* exp(-x.^2 - y.^2);

Then, create a surface plot.

surf(x,y,z)

Both thesurffunction and its companionmeshdisplay surfaces in three dimensions.surfdisplays both the connecting lines and the faces of the surface in color.meshproduces wireframe surfaces that color only the connecting lines.

Multiple Plots

You can display multiple plots in different parts of the same window using eithertiledlayoutorsubplot．

Thetiledlayoutfunction was introduced in R2019b and provides more control over labels and spacing thansubplot．For example, create a 2-by-2 layout within a figure window. Then, callnexttileeach time you want a plot to appear in the next region.

t = tiledlayout(2,2); title(t,"Trigonometric Functions") x = linspace(0,30); nexttile plot(x,sin(x)) title("Sine") nexttile plot(x,cos(x)) title("Cosine") nexttile plot(x,tan(x)) title("Tangent") nexttile plot(x,sec(x)) title("Secant")

If you are using a release earlier than R2019b, seesubplot．