newtonraphson-equation

spec.json

{
  "$schema": "https://vega.github.io/schema/vega-lite/v4.json",
  "width": 800,
  "height": 600,
  "title": {"text": "2x^3 - 4x^2 + 6", "fontSize": 20, "fontWeight": "normal"},
  "layer": [
    {
      "data": {"sequence": {"start": -4, "stop": 4, "step": 0.1, "as": "x"}},
      "transform": [
        {
          "calculate": "2 * datum.x * datum.x * datum.x - 4 * datum.x * datum.x + 6",
          "as": "y"
        }
      ],
      "mark": "line",
      "selection": {"grid": {"type": "interval", "bind": "scales"}},
      "encoding": {
        "x": {"type": "quantitative", "field": "x",  "axis":{"tickCount": 9}},
        "y": {
          "field": "y",
          "type": "quantitative",
          "scale": {"domainMin": -0.5, "domainMax": 9.5}
        },
        "color": {"value": "#f00"}
      }
    },
    {
      "data": {"values": [{"x": -1}]},
      "encoding": {"x": {"field": "x", "type": "quantitative"}},
      "layer": [
        {"mark": {"type": "rule", "strokeDash": [4, 8]}},
        {
          "mark": {
            "type": "text",
            "align": "right",
            "baseline": "bottom",
            "dx": -4,
            "dy": 10,
            "x": "width",
            "fontSize": 20,
            "text": "root = -1.0"
          }
        }
      ]
    }
  ]
}