Re: Why can't Mathematica find this root?
- To: mathgroup at smc.vnet.net
- Subject: [mg38361] Re: Why can't Mathematica find this root?
- From: "Steven Hodgen" <steven at twitch.net>
- Date: Thu, 12 Dec 2002 01:38:22 -0500 (EST)
- References: <at4dgq$f1c$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
I believe the reason may be that it expects the result to be interpreted as a repeating result. The root Pi, is simply the root 0, which it does find, in the next period of the function. So, if you view it like this: roots = 0 + k*Pi (k=+-1, +-2, +-3,...) in this case where k = 1, you get your root. I'm not 100% certain, but this may be what it assumes. --Steven "Konrad Den Ende" <konrad at voxway.com> wrote in message news:at4dgq$f1c$1 at smc.vnet.net... > Regard this function: > > f[x_] := Sin[x]^3 * Cos[x] > > And then try this: > > Solve[f'[x] == 0, x] > > and you'll get a list of all roots but one. I wonder why. > > By regarding f'[x] one can directly see that x = pi is a root, > > yet, Mathematica fails to see it... > > > Vänligen > Konrad > ------------------- > > > > >