Question
Let S be the circle in the xy-plane defined by the equation x2+y2=4. Let E1E2 and F1F2 be the chord of S passing through the point Po(1, and parallel to the x-axis and the y-axis, respectively. Let G1G2 be the chord of S passing through Po and having slop-1. Let the tangents to S at E1 and E2 meet at E3, the tangents of S at F1 and F2 meet at F3, and the tangents to S at G1 and G2 meet at G3. Then, the points E3, F3 and G3 lie on the curve.