(0 )2 1436587@9BAC9EDGF4HI 7P5QHRFTSVU0DXW6F4H
(0 )2 1436587@9BAC9EDGF4HI 7P5QHRFTSVU0DXW6F4H
(0 )2 1436587@9BAC9EDGF4HI 7P5QHRFTSVU0DXW6F4H
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182 CAPÍTULO 15. ¦£¦£ ££<br />
<br />
<br />
pA(x) = det (A − xI3) = <br />
<br />
<br />
<br />
= (2 − x) <br />
¤ <br />
A ¡<br />
−3 − x 1<br />
−3 1 − x<br />
2 − x −1 1<br />
4 −3 − x 1<br />
4 −3 1 − x<br />
<br />
<br />
+<br />
<br />
<br />
<br />
4 1<br />
4 1 − x<br />
<br />
<br />
<br />
<br />
<br />
<br />
+ <br />
4 −3 − x<br />
4 −3<br />
¢<br />
<br />
<br />
<br />
§ £ ¡ ¢ ¨ ¥ § ¢ ¡<br />
= (2 − x) ((3 + x)(x − 1) + 3) + 4(1 − x − 1) + 4(−3 + 3 + x)<br />
= (2 − x) (x 2 + 2x) − 4x + 4x = (2 − x)x (x + 2)<br />
¤ A ¢ α1 <br />
¢ <br />
<br />
= 2 α2<br />
= 0 α3<br />
= 2 ¡<br />
(2) = (0) = (−2) = 1<br />
<br />
¡<br />
¤ α1 <br />
<br />
M2<br />
M2 = {X ∈ M3×1(IR) | (A − 2I3) X = 0}<br />
<br />
= ∈ M3×1(IR) |<br />
0 −1 1<br />
4 −5 1<br />
4 −3 −1<br />
a<br />
b<br />
c<br />
0 −1 1<br />
4 −5 1<br />
4 −3 −1<br />
a<br />
b<br />
c<br />
¤ (A − 2I3) X = 0 ©<br />
<br />
<br />
M2 =<br />
=<br />
=<br />
=<br />
−−−−−→<br />
ℓ1 ↔ ℓ2<br />
a<br />
b<br />
c<br />
a<br />
b<br />
c<br />
a<br />
b<br />
c<br />
a<br />
M2<br />
a<br />
a<br />
<br />
<br />
<br />
<br />
=<br />
4 −5 1<br />
0 −1 1<br />
4 −3 −1<br />
<br />
4 −5 1<br />
−−−−→<br />
ℓ3 − ℓ1 0 −1 1<br />
0 2 −2<br />
<br />
=<br />
= −2 <br />
0<br />
0<br />
0<br />
<br />
<br />
4 −5 1<br />
−−−−−→<br />
ℓ3 + 2ℓ2 0 −1 1<br />
0 0 0<br />
∈ M3×1(IR) | 4a − 5b + c <br />
= 0 − b + c = 0<br />
∈ M3×1(IR) | 4a − 4b <br />
= 0 b = c<br />
<br />
∈ M3×1(IR) | a = b = c<br />
| b ∈ IR<br />
1<br />
1<br />
1<br />
<br />
=<br />
<br />
1<br />
1<br />
1<br />
<br />
¢<br />
(2) = dim M2 = 1