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),
=
=
2(ex+1),由此能求出其结果.
| lim |
| x→0 |
| f′(x) |
| ex-1 |
| lim |
| x→0 |
| 2(ex-1)(ex+1) |
| ex-1 |
| lim |
| x→0 |
解答:解:∵f(x)=e2x-2x,
∴f′(x)=2e2x-2=2(ex-1)(ex+1),
∴
=
=
2(ex+1)
=4.
故答案为:4.
∴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 |
=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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