If a=^i+^j+^k, b=2^i−^j+3^k and c=^i−2^j+^k find a unit vector parallel to the vector 2a - b + 3c.
We have,
a=^i+^j+^k, b=2^i−^j+3^k and c=^i−2^j+^k
Let v=2a−b+3c=2(^i+^j+^k)−(2^i−^j+3^k)+3(^i−2^j+^k)=3^i−3^j+2^k
Now, |v|=|3^i−3^j+2^k|=√32+(−3)2+22=√22
Hence, the unit vector along v is
^v=v|v|=3^i−3^j+2^k√22=(3√22^i−3√22^j+2√22^k)