Re: Find all roots with FindRoot

*To*: mathgroup at smc.vnet.net*Subject*: [mg126285] Re: Find all roots with FindRoot*From*: Andrzej Kozlowski <akozlowski at gmail.com>*Date*: Sun, 29 Apr 2012 02:07:01 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <25227796.28036.1334923020612.JavaMail.root@m06> <201204260928.FAA05588@smc.vnet.net> <201204280927.FAA00717@smc.vnet.net> <CALe_+=rU23zCn2XiYYBwUi8WcSh6m-hr4bXVAaoxszM-fBztdQ@mail.gmail.com>

On 28 Apr 2012, at 13:02, Mikael Anderson wrote: > Actually I was using NSolve and was happy with that (see below). Then I happened to see the post on RootSerach and wanted to test it to see if I get the same results as NSolve. I got surprised that by increasing the range I did not get the same answer and hence posted the question. > > BTW Andrzej, do you see any advantage in using Reduce compared to NSolve? > In Mathematica version 7 NSolve could only solve algebraic equations and Reduce could also solve transcendental (analytic) ones as well as inequalities. In version 8 NSolve can solve the same kind of equations as Reduce (I think it actually calls on Reduce to solve non-algebraic equations so you are actually using Reduce) and it even takes the options WorkingPrecision->Infinity: NSolve[x^2 - x + 1 == 0, x, WorkingPrecision -> Infinity] {{x -> (-1)^(1/3)}, {x -> -(-1)^(2/3)}} The differences, apart from the different form of output concerns solving inequalities (NSolve can't do that) and equations with symbolic parameters (NSolve can't do that but Solve can). The reason why I used Reduced is that I still sometimes forget who much Solve and NSolve were upgraded in Mathemaitca 8. Andrzej Kozlowski

**References**:**Re: Find all roots with FindRoot***From:*Mikael Anderson <mikael.anderson.1969@gmail.com>

**Re: Find all roots with FindRoot***From:*Andrzej Kozlowski <akozlowski@gmail.com>