Re: calculations in findRoot

• To: mathgroup at smc.vnet.net
• Subject: [mg100162] Re: calculations in findRoot
• From: dh <dh at metrohm.com>
• Date: Wed, 27 May 2009 04:04:37 -0400 (EDT)
• References: <gv7qv0\$ar1\$1@smc.vnet.net>

```
Hi,

unfortunately, your message is garbeled. But have a look at:

http://forums.wolfram.com/mathgroup/archive/2009/May/msg00295.html

Daniel

hesami.phy at gmail.com wrote:

> Hello,

> In my program(with mathematica 5), I want to determine rB=R(peak),rV=R

> (valley);

>  r1[l],r2[l] if vV[l]=EF=82=A3EE=EF=82=A3vB[l].

> question:

> in option FindRoot[D[vt[l,r],r]==0,{r,r0}] How I choose r0 until for

> each "l" solution rB=R(peak),rV=R(valley),r1[l],r2[l] be correct?

> Pleas guide me.

> Thanks.

>

> my program:

>

> vt[l_, r_] := v0/\((1 + Exp[\((

>     r - R0)\)/a0])\) + 1.439*\ z1\ z2\ /r\  + \ \((\((197.327)\)^2\ \ l

> \ \((

>       l + 1)\))\)/\((2\ m\ r\^2)\)\)

>

> R0=8.9436;a0=0.626;v0=-81.9;z1=8;z2=62;EE=50;l=61;m=13496.77059;hc=197.327;

>

>

> rB[l_]:=FindRoot[D[vt[l,r],r]==0,{r,10}]

>

> vB[l_]:=vt[l,r]/.{r\[Rule]rB[l][[1,2]]}

>

> rV[l_]:=FindRoot[D[vt[l,r],r]==0,{r,8}]

>

> vV[l_]:=vt[l,r]/.{r\[Rule]rV[l][[1,2]]}

>

> r1[l_]:=If[vV[l]

>   =E2=89=A4EE=E2=89=A4vB[l],FindRoot[vt[l,r]-EE==0,{r,rV[l][[1,2]],rB[l][[1,2]]}]]

>

> r2[l_]:=If[vV[l]=E2=89=A4EE=E2=89=A4vB[l],FindRoot[vt[l,r]-EE==0,{r,rB[l][[1,2]],14}]]

>

> h=CE=A9[l_]:=Sqrt[Abs[((hc)^2/m)*D[vt[l,r],{r,2}]]]%/.r\[Rule]rB[l][[1,2]];

>

> \!\(s[l_] := If[vV[

>     l] =E2=89=A4 EE =E2=89=A4 vB[

>         l], Sqrt[2*m/\((hc)\)^2]*\

>             NIntegrate[\@\((\(-EE\) + vt[l, r])\), {r, \(r1[l]\)[\

> ([1,

>           2]\)], \(r2[l]\)[\([1, 2]\)]}]] // Chop\)

>

> t[l_]:=Which[vB[l]=E2=89=A4EE,1/(1+Exp[(2 =CF=80 (vB[l]-

>       EE)/h=CE=A9[l])]),vV[l]=E2=89=A4EE=E2=89=A4vB[l],1/(1+Exp[2 s[l]]),EE=E2=89=A4vV[l],0]//Chop

>

> =CF=83[l_,EE_]:==CF=80*(hc)^2*(2 l+1)*t[l]/(2*m*EE)

>

> =CF=83[EE_]:=10 (=CF=83[0,

>   EE]+=CF=83[1,EE]+=CF=83[2,EE]+=CF=83[3,EE]+=CF=83[4,EE]+=CF=83[5,EE]+=CF=83[6,EE]+=CF=83[7,EE]+=CF=83[8,EE]+=CF=83

> [9,

>         EE]+=CF=83[10,EE]+=CF=83[11,EE]+=CF=83[12,EE]+=CF=83[13,EE]+=CF=83[14,EE]+=CF=83[15,EE]+=CF=83

> [16,

>         EE]+=CF=83[17,EE]+=CF=83[18,EE]+=CF=83[19,EE]+=CF=83[20,EE]+=CF=83[21,EE]+=CF=83[22,EE]+=CF=83

> [23,EE]+=CF=83[

>         24,EE]+=CF=83[25,EE]+=CF=83[26,EE]+=CF=83[27,EE]+=CF=83[28,EE]+=CF=83[29,EE]+=CF=83[

>         30,EE]+=CF=83[31,EE]+=CF=83[32,EE]+=CF=83[33,EE]+=CF=83[34,EE]+=CF=83[35,EE]+=CF=83[

>         36,EE]+=CF=83[37,EE]+=CF=83[38,EE]+=CF=83[39,EE]+=CF=83[40,EE]+=CF=83[41,EE]+=CF=83[

>         42,EE]+=CF=83[43,EE]+=CF=83[44,EE]+=CF=83[45,EE]+=CF=83[46,EE]+=CF=83[47,EE]+=CF=83[

>         48,EE]+=CF=83[49,EE]+=CF=83[50,EE]+=CF=83[51,EE]+=CF=83[52,EE]+=CF=83[53,EE]+=CF=83[

>         54,EE]+=CF=83[55,EE]+=CF=83[56,EE]+=CF=83[57,EE]+=CF=83[58,EE]+=CF=83[59,EE])

>

> {EE,=CF=83[EE]}

>

> ({50, 6.025565489081184`*10^-8}\)

>

>

>    but soultion below is corect.",

>

>

> {50, 6.521257897`*10^-8}

>

```

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