解,a1=s1=3+2=5
an=sn-s(n-1)=3+2∧n-(3+2∧(n-1))=2∧n-2∧(n-1)=2*2∧(n-1)-2∧(n-1)=2∧(n-1)
所以:an=2∧(n-1) a1=5
已知数列{an}的前n项和sn=3+(2的n次方),求an
已知数列{an}的前n项和sn=3+(2的n次方),求an
数学人气:870 ℃时间:2019-10-24 07:18:15
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