題組內容

2. A root locus problem is shown in Fig.2 with plan6131b42bb13f6.jpg6131b48bf1847.jpg

(c) In order to improve the stability, a zero is added in the controller as D(s)= K(s + a) to make the root locus cross the jw-axis at ±j5.5. Please find the value of a, and sketch the new root locus.(10%)