def symmetric_mass_ratio_to_mass_ratio(symmetric_mass_ratio):
    """
    Convert the symmetric mass ratio to the normal mass ratio.

    Parameters
    ----------
    symmetric_mass_ratio: float
        Symmetric mass ratio of the binary

    Return
    ------
    mass_ratio: float
        Mass ratio of the binary
    """

    temp = (1 / symmetric_mass_ratio / 2 - 1)
    return temp - (temp ** 2 - 1) ** 0.5