Solución
a.
u
=
3
x
2
+
1
u = 3x^2+1
u
=
3
x
2
+
1
b.
18
x
(
3
x
2
+
1
)
2
18x{\left( {3{x^2} + 1} \right)^2}
18
x
(
3
x
2
+
1
)
2