$\"\"$

The vector is $\"\"$ .

The standard form of the vector is $\"\"$ .

Compare the vector with general form.

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

The value of $\"\"$ is negative, hence the direction angle is $\"\"$ .

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

$\"\"$

$\"\"$ .

Direction angle is $\"\"$ .

$\"\"$

Direction angle is $\"\"$ .