之 (3) G3 ☒ P.(G)=k(k-1k3-5k2+10k-7 90.8 1 0.6 0.4 0.2 0 x t 0 0.5 1 1.5 2 1 0.5 0 0.5 1 n 9 (3) G3 — — 3 2 3 ( ) ( 1)( 5 10 7) PG kk k k k k  