Solución
∫
C
(
c
k
×
R
)
⋅
d
S
=
2
π
c
\int_C (c\bold{k}\times \bold{R})\cdot d\bold{S} = 2\pi c
∫
C
(
c
k
×
R
)
⋅
d
S
=
2
π
c