Question

what vector added to i-j+2k & i+2j-k will give a unit vector along y axis

Answer 1

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