GIA'I H^E. PHU.O.NG TRNH
186)
Gia'i h^e. phu.o.ng trnh:
dt =x+ 2y−zdzdt =x−y+ 2zHD gia’i:Phu.o.ng trnh da.c tru.ng:
(λ−1)(λ−2)(λ−3) = 0co 3 nghi^e.m
λ1
= 1;λ2
= 2; λ3
= 3.
P1i
02−λi
−1 1u.ng vo.i
λi
gia'i h^e.:
P2i
1 2−λi
−1=P3i
1 −1 2−λi
e2t
e3t
1D - u.o..c
et
;. Suy ra h^e. nghi^e.m co. ba'n
x=C2
e2t
+C3
e3t
V^a.y NTQ:
y=C1
et
+C2
e2t
z =C1
et
+C2
e2t
+C3
e3t
.dxdt =y−5 cost