an isosceles triangle is inscribed in the parabola y^2=4ax with its base as the line joining the vertex of the parabola and positive end of the latus rectum of the parabola, if (at^2, 2at) is the vertex then 1)2t^2-8t+5=0 2)2t^2+8t-5=0 3)2t^2+8t+5=0 4)2t^2-8t-5=0