已知数列{AN}的前N项和SN满足:SN+SM=S(M+N),且A1=1,那么A10=?A.1 B.9 C.10 D.5
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已知数列{AN}的前N项和SN满足:SN+SM=S(M+N),且A1=1,那么A10=?A.1 B.9 C.10 D.55
![已知数列{AN}的前N项和SN满足:SN+SM=S(M+N),且A1=1,那么A10=?A.1 B.9 C.10 D.5](/uploads/image/z/19734714-18-4.jpg?t=%E5%B7%B2%E7%9F%A5%E6%95%B0%E5%88%97%7BAN%7D%E7%9A%84%E5%89%8DN%E9%A1%B9%E5%92%8CSN%E6%BB%A1%E8%B6%B3%3ASN%2BSM%3DS%28M%2BN%29%2C%E4%B8%94A1%3D1%2C%E9%82%A3%E4%B9%88A10%3D%3FA.1+B.9+C.10+D.5)
s1=a1=1
令m=1,n=9
s1+s9=s10
则a10=s10-s9=s1=1
选A
令m=1,n=9
s1+s9=s10
则a10=s10-s9=s1=1
选A
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