<a href="http://www.codecogs.com/eqnedit.php?latex=A ( a(p@plus;q) , apq) ~ S(0,a) \\\\ Gradient~ of~ AS = \frac{apq-a}{a(p@plus;q)} \\\\ \frac{apq-a}{a(p@plus;q)} = 0 \\\\ apq - a = 0 \\\\ a(pq-1)=0 \\\\ pq = 1" target="_blank"><img src="http://latex.codecogs.com/gif.latex?A ( a(p+q) , apq) ~...