Shanghai Jiao Tong University 1、劳斯判据：例2 s4+7s3+17s2+17s+6=0 s3+4s2+10s+50=0 1 176 1 10 s3 7 170 4 50 14.57 6 0 S -2.5 0 s 14.12 00 50 0 5 6 0 0 根：3，-2，-1，-1 根：-4.35,0.17±3.39iShanghai Jiao Tong University 1. 劳斯判据：例2 1. 劳斯判据：例2 7 17 17 6 0 4 3 2 s + s + s + s + = 6 0 0 14.12 0 0 14.57 6 0 7 17 0 1 17 6 0 1 2 3 4 s s s s s 4 10 50 0 3 2 s + s + s + = 50 0 2.5 0 4 50 1 10 0 1 2 3 s s s s − 根：‐3，‐2，‐1，‐1 根： ‐4.35，0.17 ± 3.39i