Under special case ll in the Routh Hurwitz, we replace the zero row with* Coefficients of the derivative of the auxiliary equation Coefficients of the auxiliary equation Arbitrary small numbers Roots of the auxiliary equation Under special case ll in the Routh Hurwitz, the roots of the auxiliary equation are Used to replace the zeros in the zero row Actual roots of the original characteristic equation always located in the open left half plane always located in the open right half plane When designing the controller using Routh Hurwitz Criteria, we test the criteria on Closed loop characteristic polynomial Open loop characteristic polynomial Characteristic polynomial of the controller only Characteristic polynomial of the plant only