Debug of FindRoot
- To: mathgroup at smc.vnet.net
- Subject: [mg78871] Debug of FindRoot
- From: Miguel <misvrne at gmail.com>
- Date: Wed, 11 Jul 2007 06:20:24 -0400 (EDT)
To resolve one of the heat equations it is necesary to calculate the
solution of z for BesselJ[0,z]/BesselJ[1,z]==z/Bi, where Bi is the
Biot number (equal to 0.5, for example).
1.- Plot[{BesselJ[0,z]/BesselJ[1,z],z/Bi},{z,0.001,12}].
>From this plot I deduce the ranges, more or less, {1,4,7,10}.
2.- FindRoot[BesselJ[0,z]/BesselJ[1,z]==z/Bi,{z,#}]&/@{1,4,7,10}
{{z->0.940771},{z->3.95937},{z->0.940771},{z->3.95937}}
I dont understand the reason. With others differents intervals it
works fine.