**Question: ** A circle with unit radius has its centre on positive y-axis. If this circle touches the parabola y=2x^2 tangentially at the points P and Q, then the sum of their ordinates is-
**Answer: ** 15/4
**Attempt: **
I assumed tangents on the parabola as $$ y = tx - t^2/8 $$ on the points P(t1) and Q(t2). Now this is also a tangent for the circle $$x^2 + (y-k)^2 = 1$$. Putting x from the tangent to the equation of circle. The obtained equation in y should have D=0. For it has one root only. Now the obtained D=0 in t should have two roots t1 and t2. But i am not getting them as anything relevant as from the sum and product of roots.