Drexel dragonThe Math ForumDonate to the Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » Software » comp.soft-sys.math.mathematica

Topic: Is there way to use something like Assuming with the function SIgn?
Replies: 3   Last Post: Nov 24, 2012 2:40 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Bob Hanlon

Posts: 895
Registered: 10/29/11
Re: Is there way to use something like Assuming with the
Posted: Nov 24, 2012 2:40 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

"Assuming[assum, expr] evaluates expr with assum appended to
$Assumptions, so that assum is included in the default assumptions
used by functions such as Refine, Simplify, and Integrate."

list = {1, -2, a, 3};

Assuming[a < 0, Simplify[Sign[list]]]

{1, -1, -1, 1}

However, more compactly

Simplify[Sign[list], a < 0]

{1, -1, -1, 1}


Bob Hanlon


On Fri, Nov 23, 2012 at 3:25 AM, Eduardo Mendes <emammendes@hotmail.com> wrote:
> Hello
>
> I was wondering there is something similar to what can be done with Integrate, Reduce and Limit. Something like
>
> list={1,-2,a,3}
>
> Assuming[a<0,Sign[list]]
>
> Mathematica returns {1,-1,Sign[a],1} and I would like to see something like {1,-1,-1,1}. Can that be done?
>
> Many thanks
>
> Ed
>
>





Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2014. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.