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