01:03 – 軌跡的概念 | concept of a locus
03:16 – 與一點保持固定距離 | maintaining a fixed distance from a fixed point
04:45 – 與兩點保持相等距離 | maintaining an equal distance from two given points
06:52 – 與兩平行線保持相等距離 | maintaining an equal distance from two parallel lines
08:22 – 與一直線保持固定距離 | maintaining a fixed distance from a line
09:35 – 與一線段保持固定距離 | maintaining a fixed distance from a line segment
11:18 – 與兩相交直線保持相等距離 | maintaining an equal distance from two intersecting lines
13:30 – 例子 1 | example 1
14:36 – 例子 2 | example 2
16:30 – 例子 3 | example 3
18:37 – 例子 4 | example 4