Re: Question about equations solutions?
- To: mathgroup at smc.vnet.net
- Subject: [mg13164] Re: [mg13054] Question about equations solutions?
- From: Sean Ross <seanross at worldnet.att.net>
- Date: Mon, 13 Jul 1998 07:42:13 -0400
- References: <199807042044.QAA02855@smc.vnet.net.>
- Sender: owner-wri-mathgroup at wolfram.com
ieblanc at ibm.net wrote:
>
> This is probably a dumb question but can anyone help.
>
> a = Solve[y^2+5*y*x+6*x^2==0,y] gives an answer of {{y->-3 x},{y->-2
> x}}
>
> and
>
> Print[a] then displays {{y->-3 x},{y->-2 x}}
>
> How do get Print or some later input to reference the actual solutions
> "2x" or "3x" instead of {{y->-3 x},{y->-2 x}}
>
> Thanks Ian
This form of output is a transformation rule. In your case,
Map[(y/.#)&,Flatten[{{y->-3 x},{y->-2 x}},1]]
will return
{-3 x,-2 x}
and you can access the solutions as elements of the list.
The snippet of code above uses Map, from the functional paradigm along
with (y/.#)&, a pure function construct of a form from the
transformational paradigm. I learned this mostly from third party
books on mathematica programming. I recommend something like the Power
Programming book by David Wagner.
- References:
- Question about equations solutions?
- From: ieblanc@ibm.net
- Question about equations solutions?