Q40 / 59 · NEST (NISER) 2019 (Session 1) · Mathematics
For two vectors $\vec{u}$ and $\vec{v}$, define
$\vec{u} * \vec{v}=\vec{u} \times(\vec{u} \times \vec{v})+\vec{v} \times(\vec{v} \times \vec{u}) .$
Then
$\vec{u} * \vec{v}=\vec{u} \times(\vec{u} \times \vec{v})+\vec{v} \times(\vec{v} \times \vec{u}) .$
Then
- A$\vec{u} *(\vec{u}+\vec{v})=\vec{u} * \vec{v}$, for any two arbitrary vectors $\vec{u}$ and $\vec{v}$
- Correct answerB$\vec{u} * \vec{v}=\vec{v} * \vec{u}$ and $\vec{u} * \vec{u}=\overrightarrow{0}$
- Correct answerCthe angle between the vectors $\vec{u}-\vec{v}$ and $\vec{u} * \vec{v}$ is $90^{\circ}$, where $\vec{u}$ and $\vec{v}$ are two distinct non-zero vectors
- D$\vec{u} * \vec{v} \neq \overrightarrow{0}$ if $\vec{u}$ and $\vec{v}$ are distinct non-zero vectors
Hence, the correct answer is options: 'B', 'C'.