$\"\"$

The point on the polar coordinates $\"\"$ .

Rectangular coordinates conversion formula: $\"\"$ and $\"\"$ .

Consider $\"\"$ .

Substitute $\"\"$ .

$\"\"$

Consider $\"\"$ .

Substitute $\"\"$ .

$\"\"$

Therefore, the rectangular coordinate is $\"\"$ .

$\"\"$

Rectangular coordinate is $\"\"$ .