A chord is a line joining any 2 points on a curve. Its called a focal cord wen it passes thro focus. The tangent to the curve at these 2 points, when drawn n extended, will meet the directrix at rt. angles.
That is, these tangents n the directrix are concurren n the angle between the 2 tangents is a rt angle.
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There's Light at the end of every Tunnel, so KEEP MOVING....
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