apprendimento esecizio completo   =   [(1 + x2+1 x · x x2-1 ) : (2 - x2+2 x · x x2-1 ) -( x x+2 + 1 x-2 )] · x2-x-2 x2- 1   =   scompongo   =   [(1 + x2+1 x · x (x - 1)(x + 1) ) : (2 - x2+2 x · x (x - 1)(x + 1) ) -( x x+2 + 1 x-2 )] · x2-x-2 x2- 1   =   semplifica