数列{an}、{bn}中,an=3n-1,bn=4n+2,设数列{an}和数列{bn}的公共项组成数列{cn},求数列{cn}的前n项和.

问题描述:

数列{an}、{bn}中,an=3n-1,bn=4n+2,设数列{an}和数列{bn}的公共项组成数列{cn},求数列{cn}的前n项和.

∵an=3n-1,∴{an}中的各项依次为:2,5,8,11,14,17,20,23,26,29,32,35,38,41,44,47,50,53…∵bn=4n+2,∴{bn}中的各项依次为:6,10,14,18,22,26,30,34,38,42,46,50,54,58,…∵数列{a...