Plotting y=f(x) on the interval [-.1,.1]:
First create a vector of (e.g.) 200 equally spaces values between -.1 and
Suppose f(x) is an algebraic expression of standard functions such as f(x)=
Then the following computes the y values from the x values.
y1 = x1 .^ 2 .* sin(1 ./ x1);
Now put up the plot:
- Styles and colors mady be indicated e.g. by
- where r indicates red, -- indicates dashed,
: indicates dotted, and * means starred.
- Titles, xlabels, ylabels, and text can be added by
- title('Graph Illustrating ...') ; xlabel(' ... ') ; text(x0,y0,'string')
- Axes can be drawn by
- axis([xmin xmax ymin ymax])
Adding Additional Graphs:
can be accomplished by:
(Note that this function oscillates less, so we take a coarser grid with
only 50 points.
y2 = x2 .^2
y3 = -x2 .^2
Another Way to Combine Pictures:
is to use the commands
More sophisticated control of pictures is also possible via Matlab's handle graphics
- Hold on
- to cause additional pictures to be superimposed on the existing one
- Hold off
- to restore the default of replacing an old picture by a new one.
Plotting a Function Defined in an m-file:
Last Update: September 25, 2000
- Contents of m-file fcnname.m on the interval [a,b] is plotted by
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