20 Days to Go(-2 Days) Locus

The coordinates of the points A and B are (1,4) and (5,12) respectively. It is given that C is a point on the line segment AB such that AC:BC= 1:3 . L is a horizontal line passing through C.

(a) Find the coordinate of C
(b) Find the equation of L
(c) P is a moving point in the rectangular coordinate plane such that the distance between P to B is equal to the perpendicular distance between P to L. Denote the locus of P by Г.
(i) Find the equation of Г.
(ii) Describe the Г .
(iii) The Г and AB intersect at D. Find the coordinate of D .
(iv) The lowest point of Г, denoted by K, Find the area of BDK

想睇2019年DSE Math LQ同MC既參考答案CLICK呢度啦！

Locus 主要有6大類考法:
- Maintaining a fixed distance from a fixed point (Circle)
- Maintaining an equal distance from two given points (Perpendicular Bisector)
- Maintaining a fixed distance from a line (Two parallel lines)
- Maintaining a fixed distance from a line segment (Field track)
- Maintaining an equal distance from two parallel lines (A parallel straight line)
- Maintaining an equal distance from two intersecting lines (A pair of angle bisector)
但其實仲有一類大家都應該要識
但其實仲有一類大家都應該要識 , 不過可能同學仔已經遺忘左 , 就係上面例題出現嘅一種
Maintaining an equal distance from a point and a straight line (Parabola)
呢一類係近年DSE都無出現過 , 所以大家溫習時都應該要特別留意

Locus 主要有6大類考法:
– Maintaining a fixed distance from a fixed point (Circle)
– Maintaining an equal distance from two given points (Perpendicular Bisector)
– Maintaining a fixed distance from a line (Two parallel lines)
– Maintaining a fixed distance from a line segment (Field track)
– Maintaining an equal distance from two parallel lines (A parallel straight line)
– Maintaining an equal distance from two intersecting lines (A pair of angle bisector)

但其實仲有一類大家都應該要識 , 不過可能同學仔已經遺忘左 , 就係上面例題出現嘅一種
Maintaining an equal distance from a point and a straight line (Parabola)
呢一類係近年DSE都無出現過 , 所以大家溫習時都應該要特別留意