The tangent at an extremely (in the first quadrant) of latus rectum of the hyperbola $\;\large\frac{x^{2}}{4}-\large\frac{y^{2}}{5}=0\;$ , meets x -axis and y -axis at A and B respectively .Then $\;(OA)^{2}-(OB)^{2}\;$ , where O is the origin , equals : - Clay6.com, a Free resource for your JEE, AIPMT and Board Exam preparation

The tangent at an extremely (in the first quadrant) of latus rectum of the hyperbola $\;\large\frac{x^{2}}{4}-\large\frac{y^{2}}{5}=0\;$ , meets x -axis and y -axis at A and B respectively .Then $\;(OA)^{2}-(OB)^{2}\;$ , where O is the origin , equals :