![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
Let Sn = a1 + A2 + +An, let TN = S1 + S2 + +SNN is called A1, A2 The "ideal number" of the column number a 1, a 2 The ideal number of a 500 is 2004, then 8, A1, A2 The ideal number of a 500 is () A. 2004B. 2006C. 2008D. 2010
Let Sn = a1 + A2 +... + an, let TN = S1 + S2 +... + Sn / N, and call tn the ideal number of this column. It is known that the ideal number of A1, A2, A3... A500 is 2004,
So what is the ideal number of 8, A1, A2, A3... A500?
2008
The following ideal number formula is equal to [8 + (8 + S1) + (9 + S2) +. + (8 + SN)] / (n + 1)
That is [8 * 501 + S1 + S2 +.. + Sn] / (n + 1)
That is (8 * 501 + 2004 * 500) / 501 = 2008
RELATED INFORMATIONS
- 1. Let the sum of the first n terms of the arithmetic sequence {an} be Sn, if S9 = 72, then A2 + A4 + A9 = () A. 12B. 18C. 24D. 36
- 2. Given the first n terms of {an} and Sn = an2 + BN (a is not equal to 0), find the general term formula of {an} and prove that the sequence is arithmetic sequence
- 3. The first n terms and Sn of the equal ratio sequence {an} belong to N + for any n, and the point (n, Sn) is in the function y = B ^ x + R (b > 0, and B is not equal to 1, R constant) (1) Finding the value of R (2) When B = 2, denote BN = n + 1 / 4An (n belongs to N +) and find the first n terms and TN of the sequence {BN}
- 4. It is known that {an} is an equal ratio sequence with the first term A1, the common ratio Q, (q is not equal to 1, greater than 0), the sum of the first n terms is Sn, 5 * S2 = 4 * S4, let BN = q + Sn (1) It is known that {an} is an equal ratio sequence whose first term is A1, common ratio is Q, (q is not equal to 1, greater than 0). The sum of the first n terms is Sn, and 5 * S2 = 4 * S4. Let BN = q + Sn (1) find out whether the Q (2) sequence BN can be an equal ratio sequence. If we can find out Q, we can't give the reason,
- 5. Let the sum of the first n terms of the sequence {an} be Sn, and (3-m) Sn + 2man = m + 3 (n ∈ n *). Where m is a constant, m ≠ - 3 and m ≠ 0, please solve one step (2) If the common ratio of sequence {an} satisfies q = f (m) and B1 = A1, BN = 32 F (bn-1) (n ∈ n *, n ≥ 2) bn }For the arithmetic sequence, and BN If B 1 = a 1 = 1, q = f (m) = 2m m + 3, n ∈ N and N ≥ 2, BN = 32 f (bn-1) = 32 & # 8226; 2bn-1 bn-1 + 3, can we explain it? (# 8658); we get bnbn-1 + 3bn = 3bn-1 & # 8658; 1bn-1 bn-1 = 13.; {1bn} is the first term of 1, and 13 is the arithmetic sequence of tolerance, so BN = 3N + 2 Proving {1 / BN} as arithmetic sequence And find BN
- 6. In the sequence, A1 = 8, A4 = 2, and satisfy an + 2-2an + 1 + an = 0. It is proved that {an} is an arithmetic sequence
- 7. Given the sequence {an}, A1 = 1, a (n + 1) = an + 2 / an + 1. Prove that when n is greater than or equal to 2 and N belongs to positive integer, there is 1
- 8. 1. Given the sequence {an} A1 = - 2, an + 1 = (1 + an) / (1-an), then a2011= A.-2 B.-1/3 C.-0.5 D.0.5
- 9. It is known that the real number sequence an is equal ratio sequence and the common ratio is Q It is known that the real number sequence a (n) is an equal ratio sequence and the common ratio is Q. for all positive integers n > 1, there is: ((a (n + 1)) (s (n-1)) + (a (n-1)) (s (n + 1))) / 2
- 10. Let {BN} and {an} satisfy {BN} = 3an, n ∈ n *, and A1 = 1. (1) judge what kind of sequence {an} is and give the proof; (2) if CN = 1anan + 1, find the sum of the first n terms of {CN}
- 11. If a ≠ B, and a, x1, X2, B and a, Y1, Y2, Y3, B are arithmetic sequences, then (x1-x2) / (y1-y2)=
- 12. Given that 1, x1, X2, 7 are equal difference sequence, 1, Y1, Y2, 8 are equal ratio sequence, and points m (x1, Y1), n (X2, Y2), then the equation of the middle perpendicular of line Mn is______ ．
- 13. Given that the average of two groups of data x1, X2,. Xn is 5, and the average of Y1, Y2,. Yn is 2, then the average of ax1 + by1, AX2 + BY2. Axn + byn And explain the reason
- 14. It is known that x1, x2. Xn, the average number is x-pull, while ax1 + B, AX2 + B. axn + B, the average number is y-pull, which is expressed by the algebraic formula containing x-pull
- 15. x> When x is not equal to 1, lgx + (1 / lgx) = > 2 This is wrong. I don't know why. I hope someone can explain it in detail. Thank you
- 16. Lgx = - 1.5, how much is x?
- 17. Known sequence (an) satisfies: A1 = 1,2 ^ (n-1) * an = a subscript (n-1) (n is a positive integer), n ≥ 2 (1) to find the general term formula of sequence (an) Known sequence (an) satisfies: A1 = 1,2 ^ (n-1) * an = a subscript (n-1) (n is a positive integer), n ≥ 2 (1) Finding the general term formula of sequence (an) (2) The number sequence is less than 1 / 1000 from the beginning
- 18. Find sequence, 6, 666 The sum of the first n terms
- 19. If the sum of the arithmetic sequence is 2380, the tolerance is 1 and the tolerance is 3, then there are several items in the sequence
- 20. Let A1 = 125 and A10 be the first item larger than 1 in the arithmetic sequence {an}, then the tolerance D is () A. （875，+∞）B. （-∞，325）C. （875，325）D. （875，325]