Archimedean spiral
Archimedean spiral described in polar coordinates $(r,\theta)$ by the equation
$$
r=a+b\theta
$$
for real numbers $a$ and $b$. $a$ and $b$ can be controlled by sliders. The point $A$ is a glider on the curve and determines a tangent and normal to the curve.
// Define the id of your board in BOARDID
const board = JXG.JSXGraph.initBoard(BOARDID, {
boundingbox: [-20, 20, 20, -20]
});
var a = board.create('slider', [
[1, 10],
[5, 10],
[0, 1, 8]
], {
name: 'a'
});
var b = board.create('slider', [
[1, 12],
[5, 12],
[0, 0.25, 2]
], {
name: 'b'
});
var c = board.create('curve', [function(phi) {
return a.Value() + b.Value() * phi;
},
[0, 0], 0, 8 * Math.PI
], {
curveType: 'polar',
strokewidth: 4
});
var g = board.create('glider', [-1, 2, c]);
var t = board.create('tangent', [g], {
dash: 2,
strokeColor: '#a612a9'
});
var n = board.create('normal', [g], {
dash: 2,
strokeColor: '#a612a9'
});
This example is licensed under a Creative Commons Attribution 4.0 International License.
Please note that you have to mention The Center of Mobile Learning with Digital Technology in the credits.