Question

Vector must be added to the vector i cap - 3jcap +2kcap and 3i+6j-7k so that the vector is a unit vector along y axis is

Answer 1

Hey there :....

We have :
A= i-3j+2k and B= 3i +6j-7k
So here we want A+B+C= j. -(1) ( j is the unit vector along y axis)

So A+B = 4i + 3j -5k. - (2)

So by subst.( 2) in( 1) :

4i + 3j -5k. + C= j
C= j - ( 4i + 3j -5k.)
= j-4i -3j +5k
= -4i -2j + 5k

Hence, -4i -2j + 5k is the vector which must be added so that the resultant is a unit vector along y direction..