Sectors of a Circle I am programatically drawing sectors of a circle with radius 55 on a cartesian plane which runs from -55 to 55 on the x and y axes.  I would like the first sector to be drawn at 0,55.
I know I can calculate the x,y values using using:
x=radius * cos(angle) 
y=radius * sin(angle)

Further, I know that I can multiply x * -1 to go in a clockwise fashion around with the remnaing sectors.
This works great however, the first sector is positioned at -55,0 on the plane.  
How do I adjust these caculations so that the first sector starts at 0, 55 and subsequent sectors go around in a clockwise fashion from this point?

It seems like you have
incorrectly computed the offsets
into your plotting area.
If the center of the area
is supposed to be $(0, 0)$
and the array is
111 by 111 (2 x 55+1),
when you compute
$x$ and $y$,
you have to be careful
when you map those
into your plotting area.
For example,
usually $x$ goes left-to-right
and
$y$ goes bottom-to-top,
but your array to be displayed
may have
its $y$ going top-to-bottom.
