Question

If a vector 2ỉ +3j +8k is perpendicular to the vector 4j-4i + ak, then the value of a is

Answer 1

Explanation:

if two vectors are perpendicular to each other then thier dot product is equal to zero so (2i+3j+8k).(-4i+4j+ak)=0 (2)(-4) +(3)(4)+(8)(a) =0 -8+12+8a=0 4+8a=0 8a=-4

$a = \frac{ - 4}{8}$

$a = \frac{ - 1}{2}$