Another lame question : defining function by a result.



Try define(f(x),%o2); it'll work.

The reason is simple: when you define a function with :=, the RHS is NOT
evaluated. In other words, your function definition will contain the SYMBOL
%o2, not its value. When you use define(), the second argument IS evaluted:

(%i5) define(f(x),%o2);
                                             2 x + 1
                           2            ATAN(-------)
                      LOG(x  + x + 1)        SQRT(3)    LOG(x - 1)
(%o5)       f(x) := - --------------- - ------------- + ----------
                             6             SQRT(3)          3

Compare this with your line %o3.


Viktor


-----Original Message-----
From: maxima-admin@math.utexas.edu [mailto:maxima-admin at math] On
Behalf Of Jordan Tuzsuzov
Sent: Wednesday, December 22, 2004 8:08 AM
To: maxima@math.utexas.edu
Subject: Another lame question : defining function by a result.

Hello,

It is just about the expectance of work. I want to
define a function f(x) by a result of previous
calculation, related to x. Example :
(%i1) 1 / ( x^3 - 1 );
				      1
(%o1) 				    ------
				     3
				    x  - 1
(%i2) integrate(%,x);
					 2 x + 1
		       2	    ATAN(-------)
		  LOG(x  + x + 1)	 SQRT(3)    LOG(x - 1)
(%o2) 	        - --------------- - ------------- +
----------
			 6	       SQRT(3)	        3
(%i3) f(x) := %o2;
(%o3) 				  f(x) := %o2
(%i4) f(10);
					 2 x + 1
		       2	    ATAN(-------)
		  LOG(x  + x + 1)	 SQRT(3)    LOG(x - 1)
(%o4) 	        - --------------- - ------------- +
----------
			 6	       SQRT(3)	        3

The x is not substituted by 10 in call %i4. Why ?

Thanx.
Jordan


		
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