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等差数列{an}中,Sn是其前n项和,,则的值为A.2B.1C.D.3
试题详情
等差数列{a
n}中,S
n是其前n项和,
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAF8AAAAqCAYAAADVo4eHAAAAAXNSR0IArs4c6QAAAARnQU1BAACx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)
,则
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAADEAAAAxCAYAAABznEEcAAAAAXNSR0IArs4c6QAAAARnQU1BAACx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)
的值为( )
A.2
B.1
C.
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAgAAAAjCAYAAACpZEt+AAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAKVJREFU
OE/dU9ENhTAIxJVZh02YgylYAqGNlVptNO/FD0mapskB1+NYzANmEYBZwH2AsiGgsfYptYJQ8PBz
Bagoo48DikihQz0ku1gPpL4Yyh8qbMTO7mKm+374jWQzjAuFbNlUYKFiky5M46AkJahIl6GMXZXx
F9EuVziSF5oNq+NTU1MLNUZyb5/tRVmNcSdahWCeTRKLtL0hSI2D2lu9NqyJKVYckNqVrS3EAwAA
AABJRU5ErkJggg==
)
D.3
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