
Create
the 100element vector Z = 10*X  0.1*X^2, where X contains the integers
between 0 and 99.

Type
PLOT,X,Z. Examine the plot, noting the abscissa, ordinate, and default
scaling adopted.

Do
the same for PLOT,X,2*Z. Note the change.

Type
OPLOT,X,Z and note what happens

Do
the same for PLOT,X,Z^2

Do
the same for PLOT,Z^2,X

Use
the optional plotting parameters XRANGE and YRANGE with PLOT,X,Z^2 to
enlarge various parts of the plot of the Z^2 function.

Plot
log_10(X) vs. Z and X vs. log_10(Z) using the builtin PLOT_OI and PLOT_IO
commands. (Note: you'll have to limit the X,Y scales using the RANGE
parameters to avoid infinities and plot compression. Keep the variable
on the log axis greater than or equal to 1.0.)

Label
any of these plots, using the !P.TITLE, !X.TITLE, and !Y.TITLE system
variable strings. All of the plots should have appeared in Window 0.
Try alternating successive plots between Window 0 and Window 1.[NOTE:
The intrinsic IDL routines for manipulating windows are as follows: To
create a new window, use WINDOW,N. To expose or hide an existing
window, use WSHOW,N. To make a given window "active" i.e.
ready for I/Ouse WSET,N.]

Create
the 1000element vector x, where x contains the FLOATINGPOINT conversion of
integer values between 500 and +499. Create Z = 10*X  0.1*X^2 .

Using
PLOT,X,Z explore plotting features as in the previous exercise.

Type
PLOT,Z. How does the resulting plot differ from that for PLOT,X,Z?

Create
the 1000element vector X, where x contains the INTEGER values between 500
and +499. Create Y = 10*X  0.1*X^2.

Type
PLOT,X,Y. Why does the Y function differ from Z?

Now
define X to contain the integers in the range 0 to 100. Then compute Z
= SIN(X)/X. Is Z a floating point variable?

Print
the value of Z at X = 0. If you weren't sure how IDL would respond
there, how would you manually insert a value Z = 0 at X = 0? Do so.
Confirm that the z vector is now defined everywhere.

Using
the PSYM and LINESTYLE keywords, plot Z vs. X for integer values of X in the
range 0 to 100:
with a solid line
then
with plus signs
then with open triangles
then with a dashed line

Plot
Z vs. X for the X range [0:10] with open triangles. Then, using OPLOT,
add a solid line overplot.

You
can achieve the same result with a single PLOT command for your choice of
plotting symbol, K, by using PSYM=Krather than PSYM=K.

Calculate
Z = SIN(X)/X at intervals of 0.01 for X in the range 0 to 10.

Plot
Z vs X.

Using
the WHERE function, find all the locations where Z has an absolute value
smaller than 0.05. How many are there? Print Z for all those
locations (but only those locations) to your terminal.

Plot
Z vs X using a solid line. Now overplot open triangles at those points
you found where Z has an absolute value smaller than 0.05.