Solución
Tenemos
∥
u
×
v
∥
=
∥
u
∥
⋅
∥
v
∥
⋅
s
e
n
θ
=
0
2
+
4
2
+
0
2
⋅
0
2
+
0
2
+
(
−
3
)
2
⋅
s
e
n
π
2
=
4
(
3
)
(
1
)
=
12
\begin{aligned} \|\bold{u}\times\bold{v}\| &= \|\bold{u}\|\cdot\|\bold{v}\|\cdot sen\theta\\ &= \sqrt{0^2+4^2+0^2}\cdot\sqrt{0^2+0^2+(-3)^2}\cdot sen\frac{\pi}{2}\\ &= 4(3)(1)=12 \end{aligned}
∥
u
×
v
∥
=
∥
u
∥
⋅
∥
v
∥
⋅
se
n
θ
=
0
2
+
4
2
+
0
2
⋅
0
2
+
0
2
+
(
−
3
)
2
⋅
se
n
2
π
=
4
(
3
)
(
1
)
=
12