$\"\"$

The vector is $\"\"$ .

Compare the vector $\"\"$ with $\"\"$ .

$\"\"$ and $\"\"$ .

Direction angle equation :

Direction angle equation is $\"\"$ .

$\"\"$

Since $\"\"$ lies in quadrant $\"\"$ , then the value of $\"\"$ .

$\"\"$ .

$\"\"$

The direction angle $\"\"$ .