Hyperbola

The underlying JavaScript code

<jsxgraph width="500" height="500">
JXG.Options.label.autoPosition = true;
JXG.Options.text.fontSize = 16;
JXG.Options.line.strokeWidth = 0.8;

var board = JXG.JSXGraph.initBoard('jxgbox', { boundingbox: [-5, 5, 5, -5], axis: true, showClearTraces: true});

var h = board.create('hyperbola', [[-1,0], [1,0], [2, Math.sqrt(3)]]);
var l1 = board.create('line', [0, 1, 1], {dash: 1});
var l2 = board.create('line', [0, -1, 1], {dash: 1});