Dynamic tangential plane - how?
- To: mathgroup at smc.vnet.net
- Subject: [mg92909] Dynamic tangential plane - how?
- From: "m.g." <mg at michaelgamer.de>
- Date: Sat, 18 Oct 2008 06:24:40 -0400 (EDT)
Hello Group,
I=B4m trying to visualize the tangential plane to a function f(x,y). I
=B4ve done various attemps - none of them was successfull. Here an
extract of my attempts:
f[x_, y_] := (1 - x^2) (2 x - y^3)
grad[x_, y_] := {2 (1 - x^2) - 2 x (2 x - y^3), -3 (1 - x^2) y^2}
DynamicModule[{a = 1, b = 1, p, q, punkt},
{Slider2D[Dynamic[{a, b}], {{-2, -2}, {2, 2}}],
p = Plot3D[f[x, y], {x, -2, 2}, {y, -2, 2}],
punkt = Dynamic @ Graphics3D[{PointSize[Large], Red, Point[{a, b,
f[a, b]}]}],
q = Dynamic @ Plot3D[f[a, b] + grad[a, b].{x - a, y - b}, {x, -2,
2}, {y, -2, 2}]
}
]
Here the three parts I need (the surface of f, the tangential plane
and the point "punkt" where the plane touches the surface) are shown,
side by side.How can I manage it, that this three graphics are put
together in ONE Graphics.
The attempt
DynamicModule[{a = 1, b = 1, p, q, punkt},
{Slider2D[Dynamic[{a, b}], {{-2, -2}, {2, 2}}],
punkt = Dynamic @ Graphics3D[{PointSize[Large], Red, Point[{a, b,
f[a, b]}]}],
q = Dynamic @ Plot3D[{f[x, y], f[a, b] + grad[a, b].{x - a, y - b}},
{x, -2, 2}, {y, -2, 2}]
}
]
Changes f[x,y] (!!!), but only a and b are dynamically changing. How
could this happen??
Any hints appreciated.
Greeting from Germany
Mike