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Re: function that gives list of roots

• To: mathgroup at smc.vnet.net
• Subject: [mg47402] Re: function that gives list of roots
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Thu, 8 Apr 2004 05:46:00 -0400 (EDT)
• Organization: Universitaet Leipzig
• References: <c5273s$ds8$1@smc.vnet.net>
• Reply-to: kuska at informatik.uni-leipzig.de
• Sender: owner-wri-mathgroup at wolfram.com

Hi,

NthRoot[eqn_Equal, x_, n_Integer] := 
  NthRoot[eqn, x, n] = (x /. Solve[eqn, x])[[n]]

and

NthRoot[x^2 - x + 4 == 0, x, 1]

Regards
  Jens

philipp wrote:
> 
> hello
> 
> i would like to define a function, that gives me back the nth root
> (symbolic) of a given 4thorder equation; i want the result as a list
> of only expressions and not with that "x->"
> there is for sure no problem in solving the equation; i did it already
> outside the function; outside the function i also could transform the
> solutions into a normal list by using x/.%, but inside that wont work
> ...
> 
> i would be very thankful if somebody could help me
> 
> philipp