Re: Newbie Question -- Plot3d::plnc

*To*: mathgroup at smc.vnet.net*Subject*: [mg52781] Re: Newbie Question -- Plot3d::plnc*From*: "nguyen.longson at gmail.com" <nguyen.longson at gmail.com>*Date*: Mon, 13 Dec 2004 04:22:30 -0500 (EST)*References*: <cpav9n$isv$1@smc.vnet.net><cpekan$736$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

You can do what you want by typing these commands instead xtimesy = x*y; Plot3D[xtimesy, {x, -5, 5}, {y, -5, 5}] Function Plot3D doesn't consider the first argument as a function, but as a list of values of xtimesy at the specified values of x and y (the values that you defined by {x, -5, 5}, {y, -5, 5} Cheers, Helen Read wrote: > jujubaby at gmail.com wrote: > > X-No-Archive: Yes > > > > When I enter the following two statements into Mathematica 5: > > > > xtimesy[x_, y_] := x*y; > > Plot3D[xtimesy[x y], {x, -5, 5}, {y, -5, 5}] > > > > I receive a huge cascade of errors, all of this form: > > > > Plot3D::plnc: xtimesy[x\y] is neither a machine-size real number at \ > > {x,y}={-5.,-5.} nor a list of a real number and a valid color > > directive. > > > > What am I doing wrong? > > Should be > > xtimesy[x_, y_] := x*y; > Plot3D[xtimesy[x,y], {x, -5, 5}, {y, -5, 5}] > > -- > Helen Read > University of Vermont

**Follow-Ups**:**Re: Re: Newbie Question -- Plot3d::plnc***From:*DrBob <drbob@bigfoot.com>