If for two vector $\overrightarrow A $ and $\overrightarrow B $, sum $(\overrightarrow A + \overrightarrow B )$ is perpendicular to the difference $(\overrightarrow A - \overrightarrow B )$. The ratio of their magnitude is
The area of the triangle formed by $2\hat i + \hat j - \hat k$ and $\hat i + \hat j + \hat k$ is
Define the scalar product of two vectors.
${\vec A }$, ${\vec B }$ and ${\vec C }$ are three non-collinear, non co-planar vectors. What can you say about directin of $\vec A \, \times \,\left( {\vec B \, \times \vec {\,C} } \right)$ ?