Observe the graph :
\Focus
is
.
Equation of tangent line is
.
Since the point on the graph lie on
-axis,
.
Substitute
in
.


.
The point is at
and
is at
.
Find lengths of the legs of the isosceles triangle.
\

The lengths of the legs of the isosceles triangle are
.
Since the lenght of the isosceles traingle are
, the distance from
to the point of tangency
is
.
Find the tangent line distance.
\Substitute
,
and
.

Substitute
in above equation.

and 
and
.
At
, the value of
is
.
Find the the value of
at
.
Substitute
in
.


At
, the value of
is
.
The point of tangency line is located at
.
The equation of parabola is
.
Focus
is
.


Substitute
,
and
in
.



and
.
The parabola lie on above
- axis,
is positive.
Thus, the value of
is
.


Find the equation of a parabola.
\Substitute
,
and
in
.


The parabola equation is
.
The parabola equation is
.