齐次解y2(t)的形式 (1)特征根是不等实根51,S2,…,Sn (1)=k1e”+K2e2+…+K (2)特征根是等实根S1=s2=…=Sn y(t)=K1e”+K2te+…+K -1 st (引)特征根是成对共轭复根S=σ±jo,i=n/2 Wh(t)=e(,cos @, t+Kisin o, t)+.+e(K cos @, t+Ki sin a, *)齐次解yh(t)的形式 (1) 特征根是不等实根s1, s2, , sn s t n s t s t h n y t = K e + K e ++ K e 1 2 1 2 ( ) (2) 特征根是等实根s1 =s2 ==sn n st n st st h y t K e K t e K t e 1 1 2 ( ) − = + ++ (3) 特征根是成对共轭复根 ( ) ( cos sin ) ( cos sin ) 1 1 1 1 1 y t e K t K t e K t K t i i i i t t h   i     = + ++ + si = i  ji , i = n / 2