Question

What is the Cartesian form of `( 9 , (25pi)/12 )`?

Answer 1

`( 9 cos(25pi/12), 9 sin(25pi/12) )`

Explanation:

if `(r, phi) = (9, 25pi/12)`

Link between polar coordinates and Cartesian coordinates:
#x=rcos(phi), y=rsin(phi)#
r is the distance from the (0,0), and `phi` is the angle.

Now
`x = 9 cos(25pi/12)`
`y = 9 sin(25pi/12)`