, , . , , Z = (DL - SL)/ SL, , U, V .
( I . 10.6), , - , .
( II . 10.6).
. 10.6.
U 1 Z 1, V 1, U 2 Z 2, V 2. . 10.6 UV ( ), - , .
UV, , ( . 10.7), , . ( ) ( ), UV UV , , , . , / , UV UV
U
. 10.7.
j , mm ( , ), (f) , ( ), : f = f (j, V, mm).
u =
s ( ) mm UV , j UV .