Thank you!
We have:
\cdot d\;\vec{r}\;,\quad (\;\vec{r}=(x.y,z)\
" alt="\displaystyle\int_{C} f dx + g dy + h dz=\displaystyle\int_{C} \nabla F(\;\vec{r}\
\cdot d\;\vec{r}\;,\quad (\;\vec{r}=(x.y,z)\
" />
Now, apply the Gradient theorem
Fernando Revilla

