For any vector \(\vec{r}\), what is
\((\vec{r} \cdot \hat{i})(\vec{r} \times \hat{i})+(\vec{r} \cdot \hat{j})\)\((\vec{r} \times \hat{j})+(\vec{r} \cdot \hat{k})(\vec{r} \times \hat{k})\)
equal to?
1
\(\vec{0}\)
2
\(\vec{r}\)
3
\(2 \vec{r}\)
4
\(3 \vec{r}\)