ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Mon, 19 Mar 2012 23:27:41 +0100how to define a constant in sage?https://ask.sagemath.org/question/8805/how-to-define-a-constant-in-sage/Hello, I just started using sage. I am having some difficulties in declaring constants. I am trying to calculate derivatives of functions but I don't want to put values for the constant but rather define constants in the function. Somehow I am not able to find any literature on that.
I would be really grateful if someone can help me with this issue.
Cheers,
SanyogMon, 19 Mar 2012 17:51:49 +0100https://ask.sagemath.org/question/8805/how-to-define-a-constant-in-sage/Answer by John Palmieri for <p>Hello, I just started using sage. I am having some difficulties in declaring constants. I am trying to calculate derivatives of functions but I don't want to put values for the constant but rather define constants in the function. Somehow I am not able to find any literature on that.</p>
<p>I would be really grateful if someone can help me with this issue.</p>
<p>Cheers,</p>
<p>Sanyog</p>
https://ask.sagemath.org/question/8805/how-to-define-a-constant-in-sage/?answer=13378#post-id-13378The code
sage: var('x y z')
(x, y, z)
sage: f = 3*x*y + 2*z + 12
sage: f.diff(x)
3*y
sage: g(x,y,z) = 3*x*y + 2*z + 12
sage: g.diff(x)
(x, y, z) |--> 3*y
provides two slightly different ways of defining a function involving x, y, and z, then differentiating with respect to x, thus treating y and z as constants. Is this what you want?
Mon, 19 Mar 2012 21:35:55 +0100https://ask.sagemath.org/question/8805/how-to-define-a-constant-in-sage/?answer=13378#post-id-13378Comment by kcrisman for <p>The code</p>
<pre><code>sage: var('x y z')
(x, y, z)
sage: f = 3*x*y + 2*z + 12
sage: f.diff(x)
3*y
sage: g(x,y,z) = 3*x*y + 2*z + 12
sage: g.diff(x)
(x, y, z) |--> 3*y
</code></pre>
<p>provides two slightly different ways of defining a function involving x, y, and z, then differentiating with respect to x, thus treating y and z as constants. Is this what you want?</p>
https://ask.sagemath.org/question/8805/how-to-define-a-constant-in-sage/?comment=20104#post-id-20104To follow up, I think that John means just doing `var('a')` will make `a` a "symbolic constant" in the sense you desire.Mon, 19 Mar 2012 23:27:41 +0100https://ask.sagemath.org/question/8805/how-to-define-a-constant-in-sage/?comment=20104#post-id-20104