Odpowiedzi

2010-03-21T22:17:18+01:00
(x+1 )/(x-1) - (x-1)/ ( x+1) =
(x+1 )( x+1)/(x-1)( x+1) - (x-1) (x-1) /(x-1)( x+1)=

(x²+2x+1)/(x-1)( x+1) - (x²-2x+1) /(x-1)( x+1)=

=[x²+2x+1- (x²-2x+1)]/(x-1)( x+1)= =[x²+2x+1- x²+2x-1]/(x-1)( x+1)=

=[4x]/(x-1)( x+1)=4x/(x²-1)
zał.: x≠1 lub x≠-1