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mongdonguyenvong1
2 năm trước
a, S¹ = 1 + (-2) + 3 + (-4) + ... + 2001 + (-2002) b, S² = 1 + (-3) + 5 + (-7) + ... + (-1999) + 2001 c, S³ =1 + (-2) + (-3) + 4 + 5 + (-6) + (-7) + 8 + ... + 1997 + (-1008) + (-1999) + 2000. GẤP LẮM LUÔN !!! 😭😭
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