2D Plotting
Plotting y=f(x) on the interval [.1,.1]:

First create a vector of (e.g.) 200 equally spaces values between .1 and
.1.

x1=linspace(.1,.1,200);

Suppose f(x) is an algebraic expression of standard functions such as f(x)=
x^2*sin(1/x).

Then the following computes the y values from the x values.

y1 = x1 .^ 2 .* sin(1 ./ x1);

Now put up the plot:

plot(x1,y1)
 Styles and colors mady be indicated e.g. by
 plot(x,y,'r')
 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')
etc.
 Axes can be drawn by
 axis([xmin xmax ymin ymax])
Adding Additional Graphs:
can be accomplished by:

x2=linspace(.1,.1,50);

(Note that this function oscillates less, so we take a coarser grid with
only 50 points.

y2 = x2 .^2

y3 = x2 .^2

plot(x1,y1,x2,y2,x2,y3)
Another Way to Combine Pictures:
is to use the commands
 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.
More sophisticated control of pictures is also possible via Matlab's handle graphics
facility.
 Contents of mfile fcnname.m on the interval [a,b] is plotted by
 fplot('fcnname',[a,b])
Last Update: September 25, 2000
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