Re: FindRoot with complex roots
- To: mathgroup at smc.vnet.net
- Subject: [mg9762] Re: [mg9694] FindRoot with complex roots
- From: Allan Hayes <hay at haystack.demon.co.uk>
- Date: Tue, 25 Nov 1997 00:07:10 -0500
- Sender: owner-wri-mathgroup at wolfram.com
[mg9694] FindRoot with complex roots Paul Hines hines,
hines at drea.dnd.ca
writes
>I've been having trouble with the FindRoot function when the root(s) is
>complex. One such function is:
>
>r*Cos[x]+zs*Sin[x]-zwCos[x]Sin[x]/Sqrt[n^2-Sin^2[x]]=0
>
>where r,zs,zw are real and zs<0, and n complex. Typical values are
>r=100,zs=-10, and zw=20, n=1.0067+0.01I
Paul
There are some typos in
r*Cos[x]+zs*Sin[x]-zwCos[x]Sin[x]/Sqrt[n^2-Sin^2[x]]=0
if it is meant to be input:
Change
zwCos[x] --> zw Cos[x]
Sin^2[x] --> Sin[x]^2
= --> ==
Then we get
r=100;zs=-10;zw=20; n=1.0067+0.01I;
FindRoot[r*Cos[x]+zs*Sin[x]-zw*Cos[x]Sin[x]/Sqrt[n^2-Sin[x]^2]==0,
{x,4}]
{x -> 4.668031931238425 - 0.01194401062762834 I}
Allan Hayes
hay at haystack.demon.co.uk
http://www.haystack.demon.co.uk
voice: +44 (0)116 271 4198
fax: +44 (0)116 271 8642