The Lines $( 2 t + 1 ) \vec { i } + ( 1 - 3 t ) \vec { j } + ( 2 + 2 t ) \vec { k }$

Short Answer

The lines $( 2 t + 1 ) \vec { i } + ( 1 - 3 t ) \vec { j } + ( 2 + 2 t ) \vec { k }$ and $( 2 t - 3 ) \vec { i } + ( 7 - 2 t ) \vec { j } + ( - 2 + a t ) \vec { k }$ are perpendicular.Find a.