Rectangular coordinates of a point

The rectangular_coordinates command finds the rectangular coordinates of a point given its polar coordinates.

rectangular_coordinates takes two arguments: r and θ, two real numbers.
rectangular_coordinates(r,θ) returns a list of the rectangular coordinates of the point with polar coordinates r and θ.

rectangular_coordinates(2,pi/4)

or:

rectangular_coordinates(polar_point(2,pi/4))

⎡
⎢
⎢
⎣

√

⎤
⎥
⎥
⎦