This is a primer for PLOT2 (SHARE;PLOT2 PRIMER).  Please look at
SHARE;PLOT2 USAGE for full documentation of PLOT2.  (Last revision of
this file:  August 1981.)

This file contains the "Easy Examples" excerpted from PLOT2 USAGE.
    You will quite likely be able to figure out what's going on just
    from these examples.  Only read the relevant section later, if
    something is unclear.  To see the general capabilities of PLOT2 do
    DEMO(PLOT2,DEMO,DSK,SHARE); (type spaces after the plots) and
    most of these examples will be tried.

(Sec 1.1)
  PLOT2(SIN(X),X,-%PI,%PI);	plots sin(X) against X as X takes on
				PLOTNUM values between -%PI to %PI
  PLOT2(X!,X,0,6,INTEGER);	plots X! as X takes integral values
				between 0 and 6
  F(X):=SQRT(X+%PI);
  PLOT2(F(X),X,[-2,3,100.12]);	plots F(X) as X takes the values in
				the values in the list
  PLOT2([X+1,X^2+1],X,-1,1);	plots 2 curves on top of each other
(Sec 1.2)
  GRAPH2([1,2,3],[5,10,6]);	draws a line connecting [1,5], [2,10],
				[3,6]
(Sec 1.3)
  PARAMPLOT2(COS(T),SIN(T),T,0,2*%PI);	Plots cos(T) for the x-axis and
	sin(T) for the y-axis as T takes on PLOTNUM (Sec 1.5) values
	between 0 and 2*%PI.  (If EQUALSCALE is TRUE (Sec 8.3) this
	draws a circle.)
(Sec 1.4)
  LOAD('[WORLD,FASL,DSK,SHARE]);
  WORLDPLOT(-15, 10, 48, 60);	draws a map of the United Kingdom.
(Sec 3.1)
  PLOT3D(EXP(-X^2-Y^2)*X,X,-2,2,Y,-1.5,2.5);  Plots exp(-X^2-Y^2)*X as
	X takes on PLOTNUM values between -2 and 2 and y takes on
	PLOTNUM1 values between -1.5 and 2.5
  TRANSLATE:TRUE;	causes automatic translation
  G(X,Y):=(MODEDECLARE([X,Y],FLOAT),EXP(-X*X-Y*Y)); define a function G
  PLOT3D(G,-2,2,-2,2);	plot it
(Sec 3.3)
  PLOT3D(SIN(X)+A,X,-%PI,%PI,A,[-2,3,4,6],NOT3D);	plots sin(X)+A
	for X from -%PI to %PI (PLOTNUM points) and A taking the
	values in the list.  This is equivalent to:
	PLOT2([SIN(X)-2,SIN(X)+3,SIN(X)+4,SIN(X)+6],X,-%PI,%PI);
	but requires less typing.
(Sec 4.1)
  CONTOURS:10;		Do 10 contours
  LABELCONTOURS:FALSE;	Don't label the contours
  CONTOURPLOT2(Y^2/2+COS(X)+X/2,X,-6,6,Y,-3,3);		Do a contour
	plot of Y^2/2+cos(X) as X takes PLOTNUM values between -6
	and 6 and as Y takes PLOTNUM1 values between -3 and 3.
	(This gives you the phase space orbits of a particle in a
	periodic potential superimposed on a constant field).
  PLOT3D(Y^2/2+COS(X)+X/2,X,-6,6,Y,-3,3,CONTOUR);	The same
  CONTOURS:[0];		Plot only the zero contour.
  CONTOURPLOT2([REALPART((X+%I*Y)^3-1),IMAGPART((X+%I*Y)^3-1)],
	X,-1.5,1.5,Y,-1.5,1.5,[0,1]);	Finds the zeroes of Z^3=-1 in
	the complex plane.
  CONTOURS:PLOTNUM:PLOTNUM1:10;	Work with a 10x10 grid
  CONTOURPLOT2(RANDOM(100),X,0,1,Y,0,1);	Plot something random
(Sec 5.1)
  PLOT2(1,X,0,2*%PI);	Plots a straight line
  REPLOT(TRUE,POLAR);	Plots it in polar coordinates (Sec 13.1). This
	will appear as an ellipse unless EQUALSCALE:TRUE (Sec 8.3)
  EQUALSCALE:TRUE;
  REPLOT();		Replots the ellipse with EQUALSCALE equal to
	TRUE;  this will then appear as a circle.
(Sec 5.2)
  PLOTMODE(DISPLAY,XGP);	Set things up for plotting on the XGP
	and a datapoint.
(Sec 6.1)
  PLOT2(EXP(X),X,0,3,X,EXP(X),"THIS IS A PLOT OF EXP(X) VS. X");
	plots a curve of exp(X) with an x-label of "X", a y-label of
	"EXP(X)" and a tile of "THIS IS A PLOT OF EXP(X) VS. X" (the
	labels don't appear with the "'s)
  A:3;
  PLOT2(SIN(X)+A,X,-%PI,%PI,FALSE,FALSE,LABEL(A));
	plots sin(X)+A and sticks an the title "A=3".
  PLOT2(SIN(X),X,-%PI,%PI,FALSE,SIN(X)); 	labels the y-axis with
	"SIN(X)".
(Sec 9.1)
  PLOT2([SIN(X),COS(X)],X,-%PI,%PI,[0,1]);	Plots sin(X) with line
	type 0 (a solid line) and cos(X) with line type 1 (a dashed
	line)
  PARAMPLOT2(RANDOM(),RANDOM(),X,0,1,[19]);	Plots PLOTNUM
	"random" points with symbol 1 (no connecting lines drawn)
  TT:[0,1,2,3,4,5,6,7,8];
  PLOTNUM1:9;
  PLOT3D(SIN(X)+A,X,-%PI,%PI,A,0,2,TT,NOT3D);	Gives the full
	repertory of line types
  TT:9+10*(TT+1);	TT is now [19,29,39 ... ]
  REPLOT(TRUE,TT);	Gives the full repertory of symbol types.
(Sec 13.1)
  PLOT2(1,T,0,2*%PI,POLAR);	Plots a circle
  REPLOT(TRUE,LIN);		Replots the previous plot on a linear
	scale (i.e., gives a horizontal line)
  PLOT2(EXP(X),X,0,10,LINLOG);	Plots exp(X) on a Lin-Log scale
	(appears as a straight line)
  GRAPH2([1,2,5,10,50,100],[1,1.5,2.5,3,7,10],LOG);	Plots some
	random points on Log-Log scale.  Slope shows that y=sqrt(x).
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