Given that \(\vec a=5\hat i-\hat j+2\hat k\)
The unit vector of any vector \(\vec a=a_1\hat i+a_2\hat j+a_2\hat k\) can be written as
Let the required vector be \(\vec d\).
Any vector (\(\vec p\)) with magnitude m and unit vector \(\hat a\) can be written as \(\vec p=m\times\vec a\).
Since the magnitude of \(\vec d\) is 8 and it's unit vector is \(\hat a\) , we get