②PQ∑AB, then q is the midpoint (0,3) of OB,
③Q is on the x axis, OP/OQ=OB/OA,
4/OQ=6/8,OQ= 16/3,
∴Q( 16/3,0)
④PQ⊥AB, q is QR⊥Y axis in R,
PQ/OB=AQ/AO=AP/AB,PQ/6=AQ/8=4/ 10,
PQ= 12/5,AQ= 16/5,
∫QR * AP = AQ * PQ,QR =( 12/5× 16/5)÷4 = 48/25 = 1.92
AR=√(AQ^2-QR^2)=64/25=2.56,
∴OR=8-2.56=5.44,
∴Q( 1.92,5.44)。