How to do it...

To implement this recipe, perform the following steps:

1. Create the following columns in the R06_Table table:

r = 
    VAR __x = 'R06_Table'[x]
    VAR __y = 'R06_Table'[y]
RETURN
    SQRT( POWER( __x , 2 ) + POWER( __y , 2 ) )

theta = 
    VAR __x = 'R06_Table'[x]
    VAR __y = 'R06_Table'[y]
RETURN
    SWITCH(TRUE(),
        __x > 0 , ATAN( __y / __x ) ,
        __x < 0 && __y >= 0 , ATAN( __y / __x ) + PI() ,
        __x < 0 && __y < 0 , ATAN( __y / __x ) - PI() ,
        __x = 0 && __y > 0 , PI() / 2 ,
        __x = 0 && __y < 0 , -1 * PI() / 2 ,
        0
    )