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.Sun, 01 Dec 2019 17:46:45 +0100Keeping zeros after matrix multiplicationhttps://ask.sagemath.org/question/48925/keeping-zeros-after-matrix-multiplication/ Hello, Sage Community!
Suppose I do the following:
var('x y z')
u = vector([0, 1, 1])
v = vector([x, y, z])
u * v
The result is obviously `y+z`. I would like to keep the zeros after the multiplication, in order to have `0x+y+z` as my result. Is it possible?
Thanks in advance for your answers!dsejasSun, 01 Dec 2019 17:46:45 +0100https://ask.sagemath.org/question/48925/Show a multivariable function is nonvanishing when it is subject to constraintshttps://ask.sagemath.org/question/38950/show-a-multivariable-function-is-nonvanishing-when-it-is-subject-to-constraints/say we have a function $f:\mathbb R^3 \to \mathbb R$ given by
$f(x,y,z)=\sin(x)\sin(y)\sin(z)$
suppose further that there constraints $x,y,z \in (0, \pi/2)$ and $z>x+y$.
Clearly this function is nonvanishing with these constraints. Is there a way to get sage to show this? I've tried fiddling around, but I'm not sure how to do it.
I've tried
var('x,y,z')
assume(pi/2>x>0)
assume(pi/2>y>0)
assume(pi/2>z>x+y)
f=sin(x)*sin(y)*sin(z)
solve(f=0,x,y,z)
but this does not work ( I don't think I understand the solve function)Andres MejiaSat, 23 Sep 2017 16:56:19 +0200https://ask.sagemath.org/question/38950/