题目内容
在数列{an}中,a1=2,an+1=an+ln(1+
),则an=( )
| 1 |
| n |
| A.2+lnn | B.2+(n-1)lnn | C.2+nlnn | D.1+n+lnn |
∵.a2=a1+ln(1+
),
a3=a2+ln(1+
),
…
∴an=an-1+ln(1+
)
a1+ln(
)(
)(
)…(
)=2+lnn
故选A
| 1 |
| 1 |
a3=a2+ln(1+
| 1 |
| 2 |
…
∴an=an-1+ln(1+
| 1 |
| n-1 |
a1+ln(
| 2 |
| 1 |
| 3 |
| 2 |
| 4 |
| 3 |
| n |
| n-1 |
故选A
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