Table 3.

Number of possible positive real roots of Eq. (6).

Cases	Coefficients					Number of possible
	$a_{i_4}$	$a_{i_3}$	$a_{i_2}$	$a_{i_1}$	$a_{i_0}$	Positive roots
${\tilde{\mathcal{R}}}_0^{(i)}<1$	+	+/−	+/−	+/−	+	4/2/0
${\tilde{\mathcal{R}}}_0^{(i)}>1$	+	+/−	+/−	+/−	–	3/1