Capítulo 0 Álgebra vetorial - Instituto de Matemática - UFRGS
Capítulo 0 Álgebra vetorial - Instituto de Matemática - UFRGS
Capítulo 0 Álgebra vetorial - Instituto de Matemática - UFRGS
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i j k <br />
<br />
i ×i = 0, i × j = k, i × k = −j<br />
j ×i = − k, j × j = 0, j × k =i<br />
k ×i = j, k × j = −i, k × k = 0 <br />
u =i + 2j v = 3i − 2j w = u × v<br />
<br />
<br />
i <br />
w = <br />
u1<br />
<br />
j<br />
u2<br />
<br />
k <br />
<br />
u3<br />
<br />
<br />
=<br />
<br />
i <br />
<br />
1<br />
3<br />
j<br />
2<br />
−2<br />
<br />
k <br />
<br />
0 <br />
<br />
0 =i(0 − 0) + j(0 − 0) + k(−2 − 6) = −8k v1 v2 v3<br />
<br />
w =<br />
<br />
u × v = i + 2j × 3i − 2j = 3(i ×i) − 2(i × j) + 6(j ×i) − 4(j × j)<br />
= 30 − 2 k − 6 k − 40 = −8 k<br />
<br />
u v w u × (v × w) = (u × v) × w<br />
u =i v =i w = k<br />
<br />
u × u<br />
u × û<br />
u · u<br />
u · û<br />
(u + v) · (u + v)<br />
(u + v) × (u + v)<br />
(u − v) · (u − v)<br />
(u − v) × (u − v)<br />
(u + v) · (u − v)<br />
(u + v) × (u − v)<br />
00u 2 uu 2 + 2u · v + v 2 0 u 2 − 2u · v + v 2 0 u 2 − v 2 2v × u<br />
u · (v × w) = <strong>de</strong>t (u; v; w) u v <br />
w u · (v × w) > 0 u · (v × w) < 0