Given the first n terms of sequence an and Sn = 2n ^ 2 + N, the value of LIM [1 / A1A2 + 1 / a2a3 + 1 / a3a4 +... + 1 / Anan + 1] is

Sn =2n^2+n
Sn-1=2(n-1)^2+n-1
an=Sn -Sn-1
=4n-1
lim[1/a1a2+1/a2a3+1/a3a4+...+1/anan+1]
=lim[1/3*1/7+1/7*1/11+1/11*1/15
=1/4lim[1/3-1/7+1/7-1/11+1/11-1/15
=1/4*1/3
=1/12
Choose B

RELATED INFORMATIONS

1. If the quadratic power of a-ab-12b = 0, and B is not equal to 0, find 2a-b / 2A + B
2. Subtract a quarter of a number from the difference between one ninth and two fifths. What is the number? (solve the equation) Subtract a number from the difference between one ninth and two fifths to get a quarter. What's the number? (solving equations)
3. How many square meters is one mu? How many Mu is 132.3 square meters
4. (x + 1) ^ 2 - (2-x) ^ [factorization factor}] 101 ^ 3-101 ^ 2 [calculation by factorization factor]
5. It is known that the sum of the first n terms of the arithmetic sequence an is Sn, Sn = n ^ 2, sum 1 / (A1A2) + 1 / (a2a3) +. + 1 / [(an-1an] (n ≥ 2) The teacher said, use the split term elimination method to find the complete process,
6. Given that x2 + y2 = 1, x > 0, Y > 0, and loga (1 + x) = m, loga (11 − x) = n, then=______ ．
7. What is five minus two fifths
8. If a positive integer can be expressed as the square difference of two positive integers, it is called wisdom number. What is the wisdom number
9. Calculate x ^ n · x ^ n + 1 + x ^ n + 1 · x ^ n + 2 + (- x) ^ 3 · (- x) ^ 2n-4 fast line constant velocity Rt
10. Given the sum of the first n terms of the sequence {an}, Sn = + 2n, TN = 1 / (A1A2) + 1 / (a2a3) + 1 / (a3a4) +... + 1 / (Anan + 1), find TN
11. Let x-n (1.5,4) calculate P {x2.5} Let x-n (1.5,4) compute P {X & lt; = 3.5}, P {X & gt; 2.5} a problem about probability
12. How many square centimeters is one square decimeter? I've been studying for too long. I'm afraid I'll make a mistake,
13. The difference between nine tenths and two fifths subtracts a number to get a quarter. What's the number?
14. The sum problem of sequence an = 3 / (2n-11) n belongs to positive integer, and the sum of the first n terms of sequence {an} is Sn, so what is the minimum value of n with Sn ＞ 0 Summation of sequence An = 3 / (2n-11) n is a positive integer, and the sum of the first n terms of the sequence {an} is Sn, so what is the minimum value of n with Sn > 0? In addition to one written out, other clever solutions
15. Clever calculation: how to calculate 1 × 2 + 2 × 3 + 3 × 4 +... + 49 × 50? How to calculate 1 × 2 + 2 × 3 + 3 × 4 +... + 49 × 50
16. A positive integer plus 32 and 132 is equal to the complete square. How much is the positive integer?
17. (1) 15 of a number is 3.6 less than 1.6 times of 4.5. Find this number. (2) what is the difference between 6 divided by 67 and 6 divided by 67?
18. 15 16 17 18 19 20 six numbers are filled in () of the three sides of the triangle so that the sum of the three numbers on each side is 51
19. Ingenious calculation: (1 / 2 + 1 / 3) - (1 / 3 + 1 / 4) + (1 / 4 + 1 / 5) - (1 / 5-1 / 6) - (1 / 6)+ Clever calculation: （1/2+1/3）-（1/3+1/4）+（1/4+1/5）-（1/5-1/6）-（1/6+1/7）-(1/7+1/8)
20. 1 × 2 / 1 + 2 × 3 / 1 + 3 × 4 / 1 + 4 × 5 / 1 + 5 × 6 / 1