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Re: Equal and operation with list

• To: mathgroup at smc.vnet.net
• Subject: [mg29531] Re: [mg29491] Equal and operation with list
• From: Tomas Garza <tgarza01 at prodigy.net.mx>
• Date: Sat, 23 Jun 2001 01:47:16 -0400 (EDT)
• References: <200106220620.CAA24439@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

I think you can proceed like this:

In[1]:=
Clear[y, b, x];
y = {y1, y2};
b = {{b11, b12}, {b21, b22}};
x = {x1, x2};

In[2]:=
y == Dot[b,x]
Out[2]=
{y1, y2} == {b11 x1 + b12 x2, b21 x1 + b22 x2}

This is already a system of equations. For example,

In[3]:=
Solve[y == a, x]
Out[3]=
{{x1 -> -((-b22*y1 + b12*y2)/(-b12*b21 + b11*b22)), 
   x2 -> -((-b21*y1 + b11*y2)/(b12*b21 - b11*b22))}}

Tomas Garza
Mexico City

----- Original Message ----- 
From: "Guillermo Sanchez" <guillerm at gugu.usal.es>
To: mathgroup at smc.vnet.net
Subject: [mg29531] [mg29491] Equal and operation with list


> I  have tree list:
> 
> Y = {y1, y2}
> B = {{b11,b12} , {b21, b22}}
> X = {X1, X2}
> 
> I wish transform its in a system of equations like this:
> 
> {y1== b11 X1 + b12 X2, y2== b21 X1 + b22 X2}
> 
> I have test with Y == Dot[B,X] but don`t work. Any help?. Thanks
> 

• References:
  • Equal and operation with list
    • From: guillerm@gugu.usal.es (Guillermo Sanchez)