摘要:5.已知等差数列{an}.{bn}的公差分别为2和3.且bn∈N*.则数列{abn}是( ) A.等差数列且公差为5 B.等差数列且公差为6 C.等差数列且公差为8 D.等差数列且公差为9 解析:依题意有abn=a1+(bn-1)×2=2bn+a1-2=2b1+2(n-1)×3+a1-2=6n+a1+2b1-8.故abn+1-abn=6.即数列{abn}是等差数列且公差为6. 答案:B

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