ASKSAGE: Sage Q&A Forum - Latest question feedhttp://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Fri, 26 Jul 2013 01:22:04 -0500Testing inequalities in sagehttp://ask.sagemath.org/question/10388/testing-inequalities-in-sage/I wanted to show if:
$$ |a+b| \leq |a| + |b|$$
So I wrote this in sage:
var('a','b')
eqn1=abs(a+b)
eqn2=abs(a)+abs(b)
bool(eqn1<=eqn2)
The result is False.
I had expected the result to be True. What is the correct way to test this in sage?
Thank you in advance for any help provided.ensabaFri, 26 Jul 2013 01:22:04 -0500http://ask.sagemath.org/question/10388/Compare symbolic expressionshttp://ask.sagemath.org/question/10185/compare-symbolic-expressions/Following is the problem I am trying to solve:
I have multiple complex symbolic expressions f1(x1,x2,...,xn),f2(x1,x2,...,xn),...,fn(x1,x2,...,xn) which are functions of symbolic variables x1,x2,...,xn. I also have some constraints for the symbolic variables, e.g. 0 is smaller than x1, 2 is smaller than x2, x2 is integer, etc. How can I find out for two selected symbolic expressions which one is larger for given constraints?
I've tried something like:
<code> assume(0<x1,2<x2)
assume(x2,'integer')
bool(f1>f2) </code>
It seems to work for more simple symbolic expressions. For more complex symbolic expressions (where a solution definitely exists) SAGE seems not to be able to compare the expressions. Is there a way to overcome this?
KurtMMon, 03 Jun 2013 04:51:40 -0500http://ask.sagemath.org/question/10185/