Solución
∥
v
(
t
)
∥
=
s
e
c
4
t
+
s
e
c
2
t
t
a
n
2
t
=
s
e
c
2
t
(
s
e
c
2
t
+
t
a
n
2
t
)
\|\bold{v}(t)\|=\sqrt{sec^4t+sec^2ttan^2t} = \sqrt{sec^2t(sec^2t+tan^2t)}
∥
v
(
t
)
∥
=
se
c
4
t
+
se
c
2
tt
a
n
2
t
=
se
c
2
t
(
se
c
2
t
+
t
a
n
2
t
)