(1)
(x+ex)lim x→+∞
=1 x
elim x→+∞
=eln(x+ex) x
lim x→+∞
=eln(x+ex) x
lim x→+∞
=e1=e.1+ex
x+ex
(2)
令:y=
1 x
(sinlim x→∞
+cos2 x
)x=1 x
(sin2y+cosy)lim y→0
=e1 y
lim y→0
=eln(sin2y+cosy) y
lim y→0
=e2.2cos2y?siny sin2y+cosy
(3)
原式=
(1+lim x→0
)tanx?sinx 1+sinx
=1 x3
[(1+lim x→0
)tanx?sinx 1+sinx
]1+sinx tanx?sinx
tanx?sinx (1+sinx)x3
=e
lim x→0
=etanx?sinx x3
lim x→0
sinx(1?cosx) x3
=e
lim x→0