Re: Plotting 2d graphs?
- To: mathgroup at smc.vnet.net
- Subject: [mg57181] Re: [mg57168] Plotting 2d graphs?
- From: "David Park" <djmp at earthlink.net>
- Date: Fri, 20 May 2005 04:43:13 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Paul,
To plot the quadratic curve, let's first find the roots so we can better
center the plot. Notice that an equation is entered with "==" and not "=".
Solve[2x^2 + 16x + 32 == 0]
{{x -> -4}, {x -> -4}}
Since there is a double root at -4, let's plot from -24 to 16 using the Plot
statement. Notice that in the Plot statement we use only the expression that
is being plotted and not an equation.
Plot[2x^2 + 16x + 32, {x, -24, 16}];
For the ellipse we want to use ImplicitPlot and for that we have to load the
package. In ImplicitPlot we do use the equation.
Needs["Graphics`ImplicitPlot`"]
ImplicitPlot[(x - 5)^2/16 + (y + 4)^2/25 == 1, {x, 0, 10}];
For fancier plotting we could use some of the plotting options. To make the
same plot with a frame, labels and a colored background we could use...
Needs["Graphics`Colors`"]
ImplicitPlot[(x - 5)^2/16 + (y + 4)^2/25 == 1, {x, 0, 10},
Axes -> False,
Frame -> True,
FrameLabel -> {x, y},
PlotLabel -> (x - 5)^2/16 + (y + 4)^2/25 == 1,
Background -> Linen,
ImageSize -> 450];
David Park
djmp at earthlink.net
http://home.earthlink.net/~djmp/
From: Paul Hughes [mailto:psidoc at gmail.com]
To: mathgroup at smc.vnet.net
I'm having trouble using the basic 2d plot function. I want to be
able to plot things such as a simple quadratic or ellipse:
Examples: 2x^2 + 16x + 32 = 0 (Quadratic)
(x-5)^2/16 + (y+4)^2/25 = 1 (Ellipse)
But have failed to do so, having tried every variation i can think of
to get it to work.