L26A
交比的幾何意義
交比的幾何意義
0:00 The cross ratio of four distinct points is real if and only
if they are in the same generalized circle.
四相異點的交比為實數若且唯若它們落在同一個廣義圓
if they are in the same generalized circle.
四相異點的交比為實數若且唯若它們落在同一個廣義圓
2:00 Geometric Meanings of the Theorem 定理的幾何意義
22:15 Proof of Theorem 定理的證明
L26B
交比的幾何意義 (續)
交比的幾何意義 (續)
0:00 Proof of Theorem (cont.) 定理的證明 (續)
L26C
線性分式變換把圓送到圓
線性分式變換把圓送到圓
0:00 A Linear Fractional Transformation Maps Circles to Circles
線性分式變換把圓送到圓
線性分式變換把圓送到圓
2:09 Proof 證明
9:34 Symmetry 對稱
17:17 Symmetry Is Preserved by Every Linear Fractional Transformation
線性分式變換保持對稱
線性分式變換保持對稱
22:55 Cross Ratio of Symmetry Points 對稱點的交比
L26D
對稱點的交比
對稱點的交比
0:00 Proof of Theorem - Case 1 定理的證明第1種情形
2:04 Proof of Theorem - Case 2 定理的證明第2種情形
9:20 Proof of Theorem - Case 3 定理的證明第3種情形