code: public Quaterniond div(double x, double y, double z, double w) {
          final double d = x * x + y * y + z * z + w * w;
          return new Quaterniond(
                  (this.x * w - this.w * x - this.z * y + this.y * z) / d,
                  (this.y * w + this.z * x - this.w * y - this.x * z) / d,
                  (this.z * w - this.y * x + this.x * y - this.w * z) / d,
                  (this.w * w + this.x * x + this.y * y + this.z * z) / d);
      }
docs: Divides this quaternions by the double components of another one.
  
  @param x The x (imaginary) component of the quaternion to divide with
  @param y The y (imaginary) component of the quaternion to divide with
  @param z The z (imaginary) component of the quaternion to divide with
  @param w The w (real) component of the quaternion to divide with
  @return The quotient of the two quaternions