Find angle between $\vec A = 3\hat i - \hat j + 4\hat k$ and $Z-$ axis
${\tan ^{ - 1}}\,\left( {\frac{{\sqrt {22} }}{4}} \right)$
${\tan ^{ - 1}}\,\left( {\frac{{\sqrt {10} }}{4}} \right)$
${\sin ^{ - 1}}\,\left( {\frac{{\sqrt {10} }}{4}} \right)$
${\sin ^{ - 1}}\,\left( {\frac{4}{{\sqrt {26} }}} \right)$
$\hat i.\left( {\hat j \times \,\,\hat k} \right) + \;\,\hat j\,.\,\left( {\hat k \times \hat i} \right) + \hat k.\left( {\hat i \times \hat j} \right)=$
Why the product of two vectors is not commutative ?