Q. If the side $\overrightarrow{ AB }$ of an equilateral triangle $ABC$ lying in the xy plane is denoted by the vector $3i$,then side $\overrightarrow{ CB }$ is denoted by the vector, is
Vector Algebra
Solution:
$MC =3 \sin 60^{\circ}=\frac{3 \sqrt{3}}{2}$
$\overrightarrow{ MC }=\frac{3 \sqrt{3}}{2} \hat{ j } $
$\text { Now } \overrightarrow{ MC }+\overrightarrow{ CB }=\overrightarrow{ MB } $
$\frac{3 \sqrt{3}}{2} \hat{ j }+\overrightarrow{ CB }=\frac{3}{2} \hat{ i }$
$\overrightarrow{ CB }=\frac{3}{2}(\hat{ i }-\sqrt{3} \hat{ j }) $
