How to use the @mathigon/core.square function in @mathigon/core

function lineCircleIntersection(l, c) {
  const dx = l.p2.x - l.p1.x;
  const dy = l.p2.y - l.p1.y;
  const dr2 = square(dx) + square(dy);

  const cx = c.c.x;
  const cy = c.c.y;
  const D = (l.p1.x - cx) * (l.p2.y - cy) - (l.p2.x - cx) * (l.p1.y - cy);

  const disc = square(c.r) * dr2 - square(D);
  if (disc < 0) return [];  // No solution

  const xa = D * dy / dr2;
  const ya = -D * dx / dr2;
  if (nearlyEquals(disc, 0)) return [c.c.shift(xa, ya)];  // One solution

  const xb = dx * (dy < 0 ? -1 : 1) * Math.sqrt(disc) / dr2;
  const yb = Math.abs(dy) * Math.sqrt(disc) / dr2;
  return [c.c.shift(xa + xb, ya + yb), c.c.shift(xa - xb, ya - yb)];
}

function circleCircleIntersection(c1, c2) {
  const d = Point.distance(c1.c, c2.c);

  if (d > c1.r + c2.r) return [];  // Circles are separate.
  if (d < Math.abs(c1.r - c2.r)) return [];  // One circles contains the other.
  if (nearlyEquals(d, 0) && nearlyEquals(c1.r,c2.r)) return [];  // Circles are the same.
  if (nearlyEquals(d, c1.r + c2.r)) return [new Line(c1.c, c2.c).midpoint]; // Circles touch.

  const a = (square(c1.r) - square(c2.r) + square(d)) / (2 * d);
  const b = Math.sqrt(square(c1.r) - square(a));

  const px = (c2.c.x - c1.c.x) * a / d + (c2.c.y - c1.c.y) * b / d + c1.c.x;
  const py = (c2.c.y - c1.c.y) * a / d - (c2.c.x - c1.c.x) * b / d + c1.c.y;
  const qx = (c2.c.x - c1.c.x) * a / d - (c2.c.y - c1.c.y) * b / d + c1.c.x;
  const qy = (c2.c.y - c1.c.y) * a / d + (c2.c.x - c1.c.x) * b / d + c1.c.y;

  return [new Point(px, py), new Point(qx, qy)]
}

function circleCircleIntersection(c1, c2) {
  const d = Point.distance(c1.c, c2.c);

  if (d > c1.r + c2.r) return [];  // Circles are separate.
  if (d < Math.abs(c1.r - c2.r)) return [];  // One circles contains the other.
  if (nearlyEquals(d, 0) && nearlyEquals(c1.r,c2.r)) return [];  // Circles are the same.
  if (nearlyEquals(d, c1.r + c2.r)) return [new Line(c1.c, c2.c).midpoint]; // Circles touch.

  const a = (square(c1.r) - square(c2.r) + square(d)) / (2 * d);
  const b = Math.sqrt(square(c1.r) - square(a));

  const px = (c2.c.x - c1.c.x) * a / d + (c2.c.y - c1.c.y) * b / d + c1.c.x;
  const py = (c2.c.y - c1.c.y) * a / d - (c2.c.x - c1.c.x) * b / d + c1.c.y;
  const qx = (c2.c.x - c1.c.x) * a / d - (c2.c.y - c1.c.y) * b / d + c1.c.x;
  const qy = (c2.c.y - c1.c.y) * a / d + (c2.c.x - c1.c.x) * b / d + c1.c.y;

  return [new Point(px, py), new Point(qx, qy)]
}

export function variance(values) {
  if (!values.length) return null;
  let mean = mean(values);

  let sum = 0;
  for (let v of values) sum += square(v - mean);
  return sum / (values.length - 1);
}

get length() {
    return Math.sqrt(square(this.x) + square(this.y));
  }

static distance(p1, p2) {
    return Math.sqrt(square(p1.x - p2.x) + square(p1.y - p2.y));
  }