等差数列{An}中,若A1004+A1005+A1006+A1007+A1008=10,则S2011=?

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等差数列{An}中,若A1004+A1005+A1006+A1007+A1008=10,则S2011=?

等差数列{An}中,若A1004+A1005+A1006+A1007+A1008=10,则S2011=?
等差数列{An}中,若A1004+A1005+A1006+A1007+A1008=10,则S2011=?

等差数列{An}中,若A1004+A1005+A1006+A1007+A1008=10,则S2011=?
A1004+A1005+A1006+A1007+A1008=10
数列An为等差数列,则:
A1004+A1008=A1005+A1007=2A1006
即5A1006=10
A1006=2
而A1+A2011=2A1006=4
S2011=2011(A1+A2011)/2=4022

等差数列中有:A1004+A1008=A1005+A1007=2A1006
A1004+A1005+A1006+A1007+A1008=10
故有:A1006=10/5=2
故S2011=(A1+A2011)*2011/2=2A1006*2011/2=2*2011=4022

由于好久没做过数学题了,我暂时只能求到a2012=2所以很抱歉