96 Mr. Jarrett on Algebraic Notation. 



then shall /(y,y') =J\^^. ^'^) 



For, /(3,,y) = iJ„^^^.d.,r-.d..r^-Ay>y') (e- r-) 



+ S^S„^.d'-'....d\,..f{y,y'), (Art. li.) 



But, as in the last example, we shall find 



dr. .f{y. y') = rf--' • I W ■ d. ./(y, y') ] ; 

 ■■■ d",.dV./(3/,y) =d."- {^"'d..d"^.f{y,y')} 



= d.-' {^'" . d. . d=."- ' . iw^" d-, ./(3/,y)]} 



= d."-' . d-.P-' {Jy]" . 0yl " . d= . 4'/(3^, yl ; 

 since j/ and z are independent of z', and y' of s. 



