41. Using the Routh-Hurwitz criterion and the unity feedback system of Figure P6.3 with [Section: 6.4] G(s): K s(s+1)(s+2)(s+6) a. Find the range of K for stability. b. Find the value of K for marginal stability. c. Find the actual location of the closed-loop poles when the system is marginally stable. R(s) + E(s) C(s) G(s) FIGURE P6.3