If →A+→B is a unit vector along x - axis and →A=^i−^j+^k, then what is →B?
If →r×→b=→c×→b and →r.→a=0 where →a=2^i+3^j−^k,→b=3^i−^j+^k and →c=^i+^j+3^k, then →r is equal to