Question

已知无穷等差数列{a_n}中的公差为d,首项为a₁,则该数列{a_n}有有限个负项的条件是(    )

A.a₁＞0,d＞0                               B.a₁＞0,d＜0

C.a₁＜0,d＞0                               D.a₁＜0,d＜0

Answer 1

C

解析：首先满足数列为递增数列,即d＞0.

又需满足有负项,则a₁＜0.