Question

if two vector 2i+3j–k and –4i–6j–xk are parallel to each other the value of i be

Answer 1

Since the vectors are parallel, their cross product is zero.

⇒(2i^+3j^−k^)×(4i^+6j^+xk^)=0.

⇒i^(3x+6)−j^(2x+4)+k^(12−12)=0.

⇒3x+6=0 and 2x+4=0.

⇒x=−2.