Re: How to get an answer as a Root object?
- To: mathgroup at smc.vnet.net
- Subject: [mg57145] Re: How to get an answer as a Root object?
- From: "Valeri Astanoff" <astanoff at yahoo.fr>
- Date: Thu, 19 May 2005 03:08:12 -0400 (EDT)
- References: <d6bv8r$pcu$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
The trouble is the derivative being infinite at the solution.
I use that trouble to find the solution :
In[1]:=f[s_]:=
(-1+Sqrt[2]-Sqrt[(1+2*Sqrt[2]-s)*(-1+s)]+s)*(-1-Sqrt[2]+Sqrt[2]*s-
Sqrt[-1-2*Sqrt[2]+2*(2+Sqrt[2]-s)*s])-(-1-Sqrt[2]+Sqrt[2]*s+
Sqrt[-1-2*Sqrt[2]+2*(2+Sqrt[2]-s)*s])*(-2-2*Sqrt[2]+2*s+2*
Sqrt[1-(1/4)*(-1-Sqrt[2]+Sqrt[(1+2*Sqrt[2]-s)*(-1+s)]+s)^2])
In[2]:=Select[s /. Solve[Numerator[Together[1/f'[s]]] == 0], 2 < # < 3
&] // Simplify
Out[2]= 2 + 1/Sqrt[2]
In[3]:= % // N
Out[3]= 2.70711
That's not what you asked for but that's all I can do!
v.a.