Convert the following polar coordinates into rectangular coordinates.

(a) $(2,\frac \pi 4)$
$x =$ , $y =$ .

(b) $(4, \frac {2\pi}3)$
$x =$ , $y =$ .

(c) $(6, \frac{3\pi}2)$
$x =$ , $y =$ .

(d) $(6, \frac{5\pi}3)$
$x =$ , $y =$ .