def get_w_sigmoid(price_div, m_bet_size):
    """
    Part of SNIPPET 10.4
    Calculates the inverse of the bet size with respect to the regulating coefficient 'w'.
    Based on a sigmoid function for a bet size algorithm.

    :param price_div: (float) Price divergence, forecast price - market price.
    :param m_bet_size: (float) Bet size.
    :return: (float) Inverse of bet size with respect to the
        regulating coefficient.
    """
    return (price_div**2) * ((m_bet_size**(-2)) - 1)