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90 lines
3.2 KiB
TeX
Executable File
90 lines
3.2 KiB
TeX
Executable File
;;; -*- Mode:LISP; Package:MACSYMA -*-
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; ** (c) Copyright 1981 Massachusetts Institute of Technology **
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(DEFSCRIPT $ASSIGNMENT
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"In MACSYMA variables are assigned values by use of a :, for
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example, if you want to set a equal to 3, you would type"
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"a:3;"
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"and MACSYMA would respond"
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(DISPLA '3)
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"Assign a numerical value to A"
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(INCHKP 'ASSIGNCHKP)
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"The values assigned to variables may be complex, "
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(MACSYMA '((MSETQ) $C ((MTIMES) ((%COS SIMP) $X) ((%SIN SIMP) $X))))
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"The difference between expressions and functions is sometimes
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difficult to understand in MACSYMA. For example, you can type
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to MACSYMA"
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"f(x)=x^2"
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"or you could type"
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"f(x):=x^2"
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"MACSYMA will accept either form, but will treat them differently.
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The first, which looks familiar to mathematicians as a function,
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is to MACSYMA only an equation. If you ask MACSYMA to
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evaluate f(2), MACSYMA will type back F(2). The second, with
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the colon equals is the proper MACSYMA function definition for
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the function X squared."
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"Type in a simple function for f(x)."
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(FUNCHKP '(MDEFINE) '(($F) $X))
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"Now ask MACSYMA to tell you the value of this function for some
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value of X:"
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(INCHKP 'VALUEP)
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"We defined C above as SIN(X) times COS(X). Now, let's define a
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function that uses C. Type in g(x):=C^2."
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(INCHK '((MDEFINE) (($G) $X) ((MEXPT) $C 2)))
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"Notice that MACSYMA has not inserted the value of C in this function
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definition."
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"To get MACSYMA to evaluate G(X) and use the value it knows for C,
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type"
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"ev(g(x));"
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(INCHK '(($EV)(($G) $X)))
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"Now let's remove the value we assigned to C. To do this type"
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"kill(c);"
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(INCHK '(($KILL) $C))
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"Now ask MACSYMA to evaluate G(X) again."
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(INCHK '(($EV)(($G) $X)))
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"You assigned a value to A above, ask MACSYMA to evaluate the function
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F for the value of A. Type F(A)."
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(INCHK '(($F) $A))
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"When you have assigned values to a lot of variables, and defined
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a number of functions, it is important to be able to tell
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what you have assigned. MACSYMA maintains lists of these
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things for you. Type VALUES; to see a list of the variables
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to which you have assigned values."
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(INCHK '$VALUES)
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"Typing FUNCTIONS; will list the functions which you have defined."
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(INCHK '$FUNCTIONS)
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"To print out the complete function definition of one of your functions
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use the command DISPFUN, which takes the name of the function to be
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printed out as an argument. Use DISPFUN to display the definition
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of your function F."
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(CMDCHKP '(($DISPFUN) $F))
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"INFOLISTS is a list of the lists of information MACSYMA maintains.
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Type INFOLISTS; to see the names of all these lists."
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(INCHK '$INFOLISTS)
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"Typing EV(INFOLISTS); will give you a list of the things in each
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of the lists."
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(INCHK '(($EV) $INFOLISTS))
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"Checking INFOLISTS periodically during a session can help you keep
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track of the information you have in your MACSYMA. It is also
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useful for determining what information you had stored in a
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file when you reload the file (see the FILING section of the
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Primer)."
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"What would you like to go over now?"
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(PRIMER-SELECT '($INTRO $SIMPLIFICATION $SCRATCHPAD $SYNTAX $EXIT)) )
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(DEFSCRIPT $FILING
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"This script is not ready yet. Try it again in a few weeks.")
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(DEFSCRIPT $STRINGCOMMANDS
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"This script temporarily does not exist."
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)
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