Re: A 3D Plot Query
- To: mathgroup at smc.vnet.net
- Subject: [mg94249] Re: A 3D Plot Query
- From: Helen Read <read at math.uvm.edu>
- Date: Tue, 9 Dec 2008 06:56:47 -0500 (EST)
- References: <ghj01t$ff8$1@smc.vnet.net>
pcoords29 at gmail.com wrote: > Hi, > > This may sound silly, but I can't get it to work. (I'm using v 6.0) > > How do I get my 3D plots look as given in textbooks, ie. with the y- > axis pointing to the right, the z-axis up and x-axis pointing out of > the paper/screen ( showing the first octant)? I mean the kind of > plots one draws on paper when working out surface integrals in > Calculus classes. The default ViewPoint for Plot3D is ViewPoint -> {1.3, -2.4, 2.} Use ViewPoint -> {1.3`, 2.4`, 2.`} will give you the view that you are used to (x-axis point out, y-axis point to the right). > If this is of any help, I'd like to get the plot of the paraboloid > > z = 2-(x^2+y^2), as given in Fig. 10-10 of Spiegel's Advanced > Calculus, Schaum Series. This is a separate issue. See below. > I tried > > Plot3D[2 - (x^2 + y^2), {x, -a, a}, {y, -a, a}], > > with various values of a. Unfortunately, none of them look like the > traditional cap-shaped paraboloid. Is this what you are going for? Plot3D[2 - (x^2 + y^2), {x, -2, 2}, {y, -2, 2}, RegionFunction -> Function[{x, y, z}, 0 <= x^2 + y^2 <= 4]] And if you want the first octant, oriented the way you draw it on the board: Plot3D[2 - (x^2 + y^2), {x, 0, 2}, {y, 0, 2}, RegionFunction -> Function[{x, y, z}, 0 <= x^2 + y^2 <= 4], ViewPoint -> {1.3`, 2.4`, 2.`}] -- Helen Read University of Vermont