lim[√(5x-4)-√x]/(x-1)
(x→1)
=
lim[√(5x-4)-√x][√(5x-4)+√x]/{[√(5x-4)+√x]*(x-1)}
(x→1)
=lim(4x-4)/{[√(5x-4)+√x]*(x-1)}
(x→1)
=lim4/[√(5x-4)+√x]
(x→1)
=4/[√(5-4)+√1]
=4/(1+1)
=2.
这个绝对是我自己做的,楼主,相信我吧,满意的话就接受吧!