the parabola passes through (4,2) which is directly above the center
___ this means an East-West opening parabola of the form
___ the slope of the asymptotes is ±(b/a), so b=2a and b^2=4a^2
(((4-1)^2)/(a^2))-(((2-2)^2)/(4a^2))=1 ___ ((3^2)/(a^2))-0=1 ___ 3^2=a^2 ___ 3=a ___ so b=6