Routh Array a(s)=a,s6+a5s5+…+as+a0=0 06 ao a 43 a 0 S 4 aa4-a6凸 二A asaasa=B 0 as as as Aa3- BasC Aaaoas=D A0-0a=0 0 A A A 2 CB-AD =E Cao-40 S 二do 0 0 C ED E0-C0 S -Cao=F =0 0 0 E F Fao F0-E0 0 0 0 F F The number of sign changes of the first column elements of the Routh Array is equal to the number of unstable roots.Routh Array s 6 a 6 a 4 a2 a 0 s 5 a 5 a 3 a1 0 s 4 a 5 a 4  a 6 a 3 a 5  A a 5 a2  a 6 a1 a 5  B a 5 a 0  a 6 0 a 5  a 0 0 s 3 Aa 3  Ba 5 A  C Aa1  a 0 a 5 A  D A 0  0 a 5 A  0 0 s 2 CB  AD C  E Ca 0  A 0 C  a 0 0 0 s ED  Ca 0 E  F E 0  C 0 F  0 00 s 0 Fa 0  E 0 F  a 0 F 0  E 0 F  0 00 The number of sign changes of the first column elements of the Routh Array is equal to the number of unstable roots. a ( s )  a 6 s 6  a 5 s 5    a 1 s  a 0  0