Question

if the planes (2i+a j+k) =3 and (4i-j+bk),=5 are parallel then find the value of a and b​

Answer 1

Answer:

There are two other ways (which are not as simple), as given below:

Using the cross product.

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.