Question

if the vector A=ai+j-2k and B=i+ aj+k are perpendicular to each other'then find the value of 'a'

Answer 1

If 2 vectors are perpendicular then the dot product of these must be zero.

In dot product we multiply the coefficients of i , j and k of 2 vectors and add them with sign

a+a-2=0

a=1