Line Joining Tangent Intersections to Focus

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We see that the line joining the intersection to the focus bisects the angle which the tangentsí points of contact make with the focus.

Of course, if CBD is 180 degrees, then the triangle CED is right.

Expressions

Name Input
Angle DBF Eq Derive Input Maple Input MathML Input Mathematica Input Maxima Input Mupad Input TI-Nspire Input text Input Image
Angle CBF Eq Derive Input Maple Input MathML Input Mathematica Input Maxima Input Mupad Input TI-Nspire Input text Input Image