Question 1184516
<pre>

I think it's obvious that the given point had to be (p,q) in the fourth
quadrant.

All first quadrant points are {{{(

matrix(1,3,matrix(2,1,POSITIVE,NUMBER),",",matrix(2,1,POSITIVE,NUMBER)))}}}

All second quadrant points are {{{(

matrix(1,3,matrix(2,1,NEGATIVE,NUMBER),",",matrix(2,1,POSITIVE,NUMBER)))}}}

All third quadrant points are {{{(

matrix(1,3,matrix(2,1,NEGATIVE,NUMBER),",",matrix(2,1,NEGATIVE,NUMBER)))}}}

All fourth quadrant points are {{{(matrix(1,3,matrix(2,1,POSITIVE,NUMBER),",",matrix(2,1,NEGATIVE,NUMBER)))}}}

So if (p,q) is a point in the fourth quadrant, then p is 
POSITIVE and q is NEGATIVE, so -p is NEGATIVE.  So (q,-p) is 
(NEGATIVE,NEGATIVE) so it's in the third quadrant.

Edwin</pre>