In the Cesium3 documentation, there is an error in the distanceSquared documentation():
https://cesiumjs.org/Cesium/Build/Documentation/Cartesian3.html
It says:
Example:
// Returns 4.0, not 2.0
var d = Cesium.Cartesian3.distance(new Cesium.Cartesian3(1.0, 0.0, 0.0), new Cesium.Cartesian3(3.0, 0.0, 0.0));
It should be:
Example:
// Returns 4.0, not 2.0
var d = Cesium.Cartesian3.distanceSquared(new Cesium.Cartesian3(1.0, 0.0, 0.0), new Cesium.Cartesian3(3.0, 0.0, 0.0));