题目内容

设函数f(x)=e2x-2x,则
lim
x→0
f′(x)
ex-1
=
4
4
分析:由f(x)=e2x-2x,知f′(x)=2e2x-2=2(ex-1)(ex+1),
lim
x→0
f′(x)
ex-1
=
lim
x→0
2(ex-1)(ex+1)
ex-1
=
lim
x→0
2(ex+1)
,由此能求出其结果.
解答:解:∵f(x)=e2x-2x,
∴f′(x)=2e2x-2=2(ex-1)(ex+1),
lim
x→0
f′(x)
ex-1

=
lim
x→0
2(ex-1)(ex+1)
ex-1

=
lim
x→0
2(ex+1)

=4.
故答案为:4.
点评:本题考查极限的运算的应用,解题时要认真审题,仔细解答,注意导数的灵活运用.
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