Title

第26講 交比的幾何意義

Video

L26A

Syllabus

章節大綱

 

L26A
       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
       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)
        0:00 Proof of Theorem (cont.) 定理的證明 (續)
 
 
L26C
       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
       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
       22:55 Cross Ratio of Symmetry Points 對稱點的交比

 
L26D
       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