If $\bar{a}, \bar{b}, \bar{c}$ are three unit vectors such that $|\bar{a}+\bar{b}|^2+|\bar{a}+\bar{c}|^2=8$,then $|\bar{a}+3\bar{b}|^2+|\bar{a}+3\bar{c}|^2=$

Find a vector of magnitude $5$ units,and parallel to the resultant of the vectors $\vec{a}=2 \hat{i}+3 \hat{j}-\hat{k}$ and $\vec{b}=\hat{i}-2 \hat{j}+\hat{k}.$

Let $u$ and $v$ be non-collinear vectors in $\mathbb{R}^2$. Let $w$ be the orthogonal projection vector of $u$ on $v$. Consider two statements:
$(i)$ Any vector in $\mathbb{R}^2$ can be written as a linear combination of $u$ and $v$.
(ii) $w$ can be written as a linear combination of $u$ and $v$ as $w = au + bv$,where both $a$ and $b$ are non-zero real numbers.

Statement $(A):$ In $\Delta ABC$,$\overline{AB} + \overline{BC} + \overline{CA} = 0$.
Reason $(R):$ If $\overline{AB} = \vec{a}$ and $\overline{BC} = \vec{b}$,then $\overline{AC} = \vec{a} + \vec{b}$ (Triangle Law of Addition).

If two vertices of a triangle are $\hat{i} - \hat{j}$ and $\hat{j} + \hat{k}$,then the third vertex can be

If $\bar{a}$ and $\bar{b}$ are two non-parallel unit vectors and the vector $\alpha \bar{a} + \bar{b}$ bisects the internal angle between $\bar{a}$ and $\bar{b}$,then $\alpha$ is equal to