Question

Problem 18

Answer 1

Given information

Let p(x1,y1)) be a point on the parabola  with focus  as shown in the figure.

We want to show that the angle between the tangent at a point P and the line joining the focus and point P is equal the angle between the tangent at point P and the horizontal line passing through point P.

Step-by-step explanation

Step 1.

Construction : Let the horizontal line passing through point P meet the directrix ar point A.

Join AP and AF. Let the line segment AF meet the tangent at point P at B.