def METHOD_NAME(self, u, x, y, n_sersic, q, R_sersic, k_eff, n_integral):
    kappa = self.projected_mass(x, y, q, n_sersic, R_sersic, k_eff, u=u, power=1)
    power = -(n_integral + 0.5)
    return kappa * (1 - (1 - q**2) * u) ** power