What is \(\rm \left( {\vec a + \vec b} \right) \times \left( {\vec a - \vec b} \right)\)equal to?
1
0
2
\(\rm -2\left( {\vec a \times \vec b} \right)\)
3
\(\rm 2\left( {\vec a \times \vec b} \right)\)
4
\(\rm {\left| {\vec a} \right|^2} - {\left| {\vec b} \right|^2}\)