问题 填空题
已知等差数列{an}满足:a1005=
3
,则tan(a1+a2009
)=______.
答案

∵等差数列中a1005=

3

a1+a2009=2a1005=

3

∴tan(a1+a2009

=tan

8
3
π

=-tan

π
3

=-

3

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