割圆术计算 PI

const getSideLength = (sideLength, count) => {
  if (count <= 0) return sideLength;
  const m = sideLength / 2;
  const g = Math.sqrt((0.5 ** 2) - (m ** 2));
  const j = 0.5 - g;
  return getSideLength(Math.sqrt((j ** 2) + (m ** 2)), count - 1);
};



const pi = (splitCount = 0) => {
  const sideLength = getSideLength(0.5, splitCount);
  const sideCount = 6 * (splitCount ? 2 ** splitCount : 1);
  return sideLength * sideCount;
};