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Topic: Trouble finding the roots of an equation
Replies: 3   Last Post: Nov 30, 2012 12:24 PM

 Messages: [ Previous | Next ]
 Nasser Abbasi Posts: 5,062 Registered: 2/7/05
Re: Trouble finding the roots of an equation
Posted: Nov 30, 2012 12:04 PM

On 11/30/2012 10:47 AM, Marcio Barbalho wrote:
> Dear friends
> salve salve!
>
> I'm trying to find n roots for this equation y = x*tan(x)-10.

around where? here are some roots

EDU>> x=-2*pi:.1:2*pi; %have a quick look first to get an idea
EDU>> plot(x,x.*tan(x)-10)
EDU>> sol=fsolve(@(x) x.*tan(x)-10,0.01:1:10);
EDU>> sol'

ans =

1.428870011214077
1.428870011214077
7.228109771675751
4.305801413119223
4.305801413119223
7.228109771627249
7.228109771627249
7.228109771627249
10.200262588295905
10.200262588295905

>
> It seems I'll have to include symbolic calculation, which I
>was trying to avoid in order to speed up the processing!
> So I wonder how I could transform y into a series and get n of its infinite roots.
>
> Any help will be very much appreciated!
>

--Nasser

Date Subject Author
11/30/12 Marcio Barbalho
11/30/12 Nasser Abbasi
11/30/12 Marcio Barbalho
11/30/12 Roger Stafford