Re: Plot Question
- To: mathgroup at smc.vnet.net
- Subject: [mg6848] Re: [mg6797] Plot Question
- From: "Sherman.Reed" <sherman.reed at worldnet.att.net>
- Date: Thu, 24 Apr 1997 02:44:29 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Ivan, the problem is the following. for negative values of x, the cube root is a complex number. When I encounter similar problems with plot, I use the Table command to see what is being created. Frequently, the answer is then obvious. Sherman C. Reed sherman.reed at worldnet.att.net ---------- > From: Ivan G. Burch II <ivanb at hula.net> To: mathgroup at smc.vnet.net > To: mathgroup at smc.vnet.net > Subject: [mg6848] [mg6848] [mg6797] Plot Question > Date: Sunday, April 20, 1997 12:50 AM > > Folks, > > > It has been a long time since I plotted anything on the MMA program. > > I would however like to know why this is not plotting correctly, The > math for this is completely sound by the way. > > > I want to have MMA plot the following: > > Plot[{-x^3, -x^(1/3), x}, {x, -10, 10}] > > I get the following errors for this: > Plot::plnr : -x^(1/3) is not a machine-size number at x = -10 > " " " " " " " " " " " x = -9.18866 > " " " " " " " " " " " x = -8.30382 > > > I have tried to expand the restrict values to no end. Any information > would be helpful in this matter. > > Note the the following does graph correctly: > -x^3 > x > and only part of the graph for the third. > > > Do not understand why it is doing this > please send information to email address listed below I will get it > faster > > > > Thanks for any help in this!! > > > > > > Sincerely, > > > > > Ivan G. Burch II aka enforcer > at email address: > "ivanb at hula.net"