Re: Solve question

• To: mathgroup at smc.vnet.net
• Subject: [mg57466] Re: [mg57457] Solve question
• From: Bob Hanlon <hanlonr at cox.net>
• Date: Sun, 29 May 2005 01:03:25 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

```eqn=a*x^2+b*x+c==0;

soln=Solve[eqn,x]

{{x -> (-b - Sqrt[b^2 - 4*a*c])/(2*a)},
{x -> (Sqrt[b^2 - 4*a*c] - b)/(2*a)}}

The result is a set of rules, {lhs -> rhs}.  Rules are used with Replace,
ReplaceAll ( /. ), or ReplaceRepeated ( //. ).  For example, verifying that the
solutions satisfy the original equation:

eqn/.soln //Simplify

{True,True}

Bob Hanlon

>
> From: "Sterritt, Lanny" <lanny.sterritt at lmco.com>
To: mathgroup at smc.vnet.net
> Date: 2005/05/28 Sat AM 05:39:41 EDT
> Subject: [mg57466] [mg57457] Solve question
>
> When the Solve command is used to obtain the value of a variable in an
equation, something like  {x -> value}  is returned.  How does one get
Mathematica  to automatically apply this value to following  expressions in a
notebook?
>
> L.W.Sterritt
>
>

```

• Prev by Date: Re: Re: Re: Applying a list of functions to a list of arguments
• Next by Date: Re: Limit of list
• Previous by thread: Re: Solve question
• Next by thread: Re: Solve question