What is the angle between $\overrightarrow P $ and the resultant of $(\overrightarrow P + \overrightarrow Q )$ and $(\overrightarrow P - \overrightarrow Q )$

Establish the following vector inequalities geometrically or otherwise:

$(a)$ $\quad| a + b | \leq| a |+| b |$

$(b)$ $\quad| a + b | \geq| a |-| b |$

$(c)$ $\quad| a - b | \leq| a |+| b |$

$(d)$ $\quad| a - b | \geq| a |-| b |$

When does the equality sign above apply?

While travelling from one station to another, a car travels $75 \,km$ North, $60\, km$ North-east and $20 \,km $ East. The minimum distance between the two stations is.......$km$

Magnitudes of two vector $\overrightarrow A $ and $\overrightarrow B $ are $4$ units and $3$ units respectively. If these vectors are $(i)$ in same direction $(\theta = 0^o).$ $(ii)$ in opposite direction $(\theta = 180^o)$, then give the magnitude of resultant vector.

If $\vec A$ and $\vec B$ are two non-zero vectors such that $\left| {\vec A + \vec B} \right| = \frac{{\left| {\vec A - \vec B} \right|}}{2}$ and $\left| {\vec A} \right| = 2\left| {\vec B} \right|$ then the angle between $\vec A$ and $\vec B$ is

If $\vec{P}+\vec{Q}=\overrightarrow{0}$, then which of the following is necessarily true?