View previous topic :: View next topic 
Author 
Message 
GiovanniParodi Newbie
Joined: 10 Jun 2005 Posts: 2

Posted: Fri Jun 10, 2005 4:49 am Post subject: Equation Systems... how to? 


Hello everybody, I need to create an equation system with Math, but I'm not able to do that.
How can I create a system with the following equations
x = a+b
y = c+d
?
In fact I tried
lbrace x=a+b {} newline y=c+d
but it doesn't work because there's not the rbrace..
But I don't want the rbrace, so how can I do?
Thanks a lot Giovanni 

Back to top 


David Super User
Joined: 24 Oct 2003 Posts: 5668 Location: Canada

Posted: Fri Jun 10, 2005 5:13 am Post subject: Re: Equation Systems... how to? 


GiovanniParodi wrote:  Hello everybody, I need to create an equation system with Math, but I'm not able to do that.
How can I create a system with the following equations
x = a+b
y = c+d
?
In fact I tried
lbrace x=a+b {} newline y=c+d
but it doesn't work because there's not the rbrace..
But I don't want the rbrace, so how can I do?
Thanks a lot Giovanni 
Hi, Giovanni.
First of all, that is not strictly a "system" of linear equations in two variables "x" and "y", which might look more like this:
2x + 3y = 7
3x  5y = 1
You don't need the math editor for that. Just use the word processor. The editor is not a symbolic algebra program ...it won't calculate, just present the symbols. The symbols you use here are available in the word processor from the keyboard. The math editor is primarily for those symbols and formats not otherwise available from the keyboard. To do abstract algebra calculations, you'd need a pogram like Mupad, Maple, Derive, Mathematica, and so on. You can set up a spreadsheet to do numerical calculations, as in finding solutions to the linear system 3x + 2y = 5, 2x  3y = 7. If simply wanting the appearance shown, you've already done it when you typed your request here:
x = a+b
y = c+d
but can do no further calculation on that set of statements.
I suspect that's what you want, since you already have the "solution" format for "x" and "y".
David.
Last edited by David on Fri Jun 10, 2005 5:26 am; edited 2 times in total 

Back to top 


RGB Super User
Joined: 25 Nov 2003 Posts: 1743 Location: In Lombardy, near a glass of red Tuscany wine

Posted: Fri Jun 10, 2005 5:20 am Post subject: 


The right brace could be replaced be the command:
BUT, you cannot put a line break between braces. Instead of that, use a matrix or stack
Code:  left lbrace stack{x=a+b#y=c+d} right none 
If you need the equal signs at the same level, use a matrix
Code:  left lbrace matrix{x # "=" # a+b ## y # "=" # c+d} right none 


Back to top 


GiovanniParodi Newbie
Joined: 10 Jun 2005 Posts: 2

Posted: Fri Jun 10, 2005 5:26 am Post subject: 


Thans a lot to everybody,
in fact my english is not as good as yours
The correct answer to my doubts ha been placed by RGB, I want only a symbolic representation of an equation system...
However thanks a lot also to David for his kindness...
thanks again Giovanni 

Back to top 


richardf OOo Enthusiast
Joined: 10 Oct 2004 Posts: 107

Posted: Sat Jun 11, 2005 7:47 am Post subject: 


I usually do it as follows:
left lbrace binom {alignl x = a + b} {alignl y = c+d} right none
Richard 

Back to top 


Piter_ General User
Joined: 13 Nov 2011 Posts: 10

Posted: Sun Nov 13, 2011 5:20 am Post subject: 


Hi. Is it possible to assign separate number to each of the equation in the system? If I make a system as described above it is numbered as one equiaton.
Thanks 

Back to top 


Robert Tucker Moderator
Joined: 16 Aug 2004 Posts: 3407 Location: Manchester UK


Back to top 


