Find the point of intersection of the tangent lines.

Hi I need to write a function in Python, in which I have to find the point of intersection of two tangents of a circle.
I just need the mathematical formula. I would appreciate your help.

Following are the details:

We are given following two information:
(1) Two points on the circumference of a circle: P (x1, x2) and Q (y1, y2)
(2) The angle (A) at the intersection of the two tangent lines through the points P and Q.

To find: The point (x, y) at the intersection of the tangent lines.

Thank you.

Or alternatively it will work for me if we could find the CENTER of the circle when the two points at the circumference and the angle at the center of the circle are given.