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Re: solving nonlinear equation with mathematica !!

• To: mathgroup at smc.vnet.net
• Subject: [mg47189] Re: solving nonlinear equation with mathematica !!
• From: "Peter Pein" <no at spam.no>
• Date: Mon, 29 Mar 2004 04:22:35 -0500 (EST)
• References: <c438oj$ekr$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

"why" <m004202002 at yahoo.com> schrieb im Newsbeitrag
news:c438oj$ekr$1 at smc.vnet.net...
> Hi,
>
> I face root finding problem solving nonlinear equation
>
> I have system nonlinear equation
>
> x^2-y-1 = 0;
> 10x exp(-x)-y = 0 ;
>
> If you draw the graph you see two intersecting point .
>
> I have found a point [Using FindRoot function ]
> In (-0.1,-0.5) the point is (-0.0905897,-0.991794 )---it is OK
>
> But
> In (2.0,1.0) the point is (1.94463,2.7816)
> But the graph says the x->2.something ,y->1.somthing
> I have used same FindRoot function to find the root
> in (2.0,1.0 ).
>
> Please help me ASAP .
>
> ..
> I want(exam)to use other methods(bisection/secant etc).
> If any one have workout examples of nonlinear equation
> please let me know .
> .....
>
> Thank You .
>

Plot[x^2 - 10 x E^x - 1, {x, -1/2, 5/2}]

shows the root beeing < 2 in Mathematica 4.0, as

ImplicitPlot[{x^2 - y == 1, 10x Exp[-x] == y },
  {x, -1/2, 5/2}, {y, -3/2, 3}, AxesOrigin -> {2, 0}];

does.

Peter
-- 
Peter Pein, Berlin
StringReplace["petsie at arcand.de",
 Rule@@(ToLowerCase@ToString@Head@#&)/@{William&&S,2b||!2b}]