GIA'I H^E. PHU.O.NG TRNH
183)
Gia'i h^e. phu.o.ng trnh:
dt =y−x+zdzdt =x−z1−λ −2 −1−1 1−λ 1= 0⇔λ(λ2
−λ−2) = 0HD gia’i:Phu.o.ng trnh da.c tru.ng
1 0 −1−λ⇔λ1
= 0, λ2
=−1, λ3
= 2P1i
1−λi
−2 −1Vo.i cac
λi
; i= 1,2,3gia'i h^e.:
−1 1−λi
1P2i
= 0P3i
1 0 −1−λi
D - ^e' tm nghi^e.m ri^eng tu.o.ng u.ng. Tu. do suy ra h^e. nghi^e.m co. ba'n:
x1
= 1, y1
= 0, z1
= 1; x2
= 0, y2
=e−t
, z2
=−2e−t
; x3
= 3e2t
,y3
=−2e−2t
, z3
=e2t
.
x=C1
+ 3C3
e2t
V^a.y h^e. nghi^e.m t^o'ng quat:
y=C2
e−t
−2C3
e2t
z =C1
−2C2
e−t
+C3
e2t
dxdt −5x−3x= 0