两个等差数列{a
n},{b
n},
=,则
=( )
A.
B. 7
C.
D.
人气:471 ℃ 时间:2019-10-11 12:10:11
解答
由题意可设等差数列{a
n},{b
n}的前n项和分别为S
n和T
n,
∴
=
=,
∴
=
=
=
=
=
=
故选:D
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