Question

若等差數(shù)列{a_n}滿足a₂+S₃=4，a₃+S₅=12，則a₄+S₇的值是

1. A.
   20
2. B.
   36
3. C.
   24
4. D.
   72

Answer 1

C
分析：由等差數(shù)列的性質(zhì)轉(zhuǎn)化a₂+S₃=4a₂，a₃+S₅=6a₃，a₄+S₇=8a₄，再求解．
解答：由等差數(shù)列的性質(zhì)得a₂+S₃=4a₂=4，a₃+S₅=6a₃=12，
∴a₂=1，a₃=2
∴a₄=3
∴a₄+S₇=8a_4⁼²⁴
故選C
點(diǎn)評(píng)：本題主要考查等差數(shù)列的性質(zhì)．