If (m;, 1/m;),i = 1,2,3,4 are concyclic points, then the value of m1 m2 m3 m4, is

Let the equation of the circle bex2+y2+2gx+2yy+c=0.If (m, 1 Im) Lies on this circle, thenm2+1m2+2gm+2f1m+c=0⇒ m4+2gm3+2fm+cm2+1=0This is a fourth degree equation in m having m1,m2,m3,m4 as its roots.∴   Product of the roots =1⇒m1m2m3m4=11=1