Ellipse :4x2+3y2=1 eccentricity =1−43=21∴ foci =(±1,0) for hyperbola, given 2a=2⇒a=21∴ hyperbola will be 21x2−b2y2=1 eccentricity =1+2b2∴ foci =(±21+2b2,0) Ellipse and hyperbola have same foci ⇒21+2b2=1⇒b2=21∴ Equation of hyperbola :21x2−21y2=1⇒x2−y2=21 Clearly (23,21) does not lie on it.