# Geo5.1.49

From Example Problems

Show that the tangent at one extremity of a focal chord of a parabola is parallel to the normal at the other extremity.

Let be the two extremeties of a focal chord

of the given parabola.

Equation of the tangent at P is . equation 2

Slope of this equation is .

Equation of the normal at Q is

Slope of the normal is which is the slope of

the equation 2.

Therefore tangent at P is parallel to the normal at Q.