Question

Find the unit vector perpendicular to the vectors A= 3i^ + j^ and B= 2i^ +j^ +5k^

Answer 1

Answer:

Let a = 2i – j + k and b= 3i – 4j – k.

A unit vector perpendicular to a and b

= ± ((a × b)/(|a × b|))

Now,

(draw the image here)

= 5i + 5j – 5k = 5(i + j – k)

Thus, the unit vector = ± ((a × b)/(|a × b|))  

= ± (1/√3)(i + j – k).