522 



BELL SYSTEM TECHNICAL JOURNAL 



Y= Y° + Y' 



//////6//////////////x/////x.dx 



FI6.2 



f(x) f(xtdx) 



F(x) F(x+dx) 



Zo 



:Y'dx 



Y'dx I Y'dx 



^Y'dx 



//////6//////////////;/////x.dx //////////// s 



FI6.3 



f(x)dx 



-L ^i— 



^F(x) 



:Y'dx 



T 'I r 



■F(x+dx) 



Y'dx 



Y'dx 



Y'dx 



7777770 



x.dx //////////// S ///// 



FI6.4(SETI) 



f(x)dx 



777777077777777/ 



FI6.5 



f(x)dx 



~^ ~^ ~tY r/..\ nr JL ""^ "^ 



Ydx' 



Ydx I Ydx I Ydx 



777777o77777777//77//x/////-K.<ix 



FI6.6(SET5) 



'7777 k 77777 



