$\"\"$

The vector is $\"\"$ .

The general form of vector is $\"\"$ .

The angle between the vector and the positive $\"\"$ -axis is $\"\"$ .

Compare the vector with general form.

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

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

$\"\"$

Therefore, the angle is $\"\"$ .

$\"\"$

The angle is $\"\"$ .