Look at the following list: half, one sixth, one twelfth, one twentieth Please find out the rule of arrangement and press here Fill in the blank regularly The fifth number is—— The number in 2011 is——

Look at the following list: half, one sixth, one twelfth, one twentieth Please find out the rule of arrangement and press here Fill in the blank regularly The fifth number is—— The number in 2011 is——

The k-th number is 1 / (k * (K + 1))
The fifth number is 1 / (5 * 6) = 1 / 30
The number of 2011 is 1 / (2011 * 2012) = 1 / 4046132

According to the rule of 1, 1 / 2, 1 / 4, 1 / 8 and 1 / 16, what is the 100th number

One to the 99th power of 2

According to a certain rule, a column of data is arranged as follows: 1 / 2, 1 / 3, 1 / 10, 1 / 15, 1 / 26, etc., then the 11th one What is the eleventh number?

One in 122
2=1*1+1,
3=2*2-1,
10=3*3+1,
15=4*4-1,
26=5*5+1,
The 11th is: 11 * 11 + 1 = 122

According to a certain rule, a column of data is arranged as follows: half, one third, one tenth, one fifteenth, and one twenty sixth What's the nth number?

When n is odd, 1 / (N 2 + 1)
When n is even, 1 / (n? - 1)

What is the fifteenth, the sixth, the tenth

1/2=1/(1^2+1)
1/3=1/(2^2-1)
1/10=1/(3^2+1)
1/15=1/(4^2-1)
1/26=1/(5^2+1)
1/35=1/(6^2-1)
Rule: the numerator is 1; the denominator of odd number term is the square of item number + 1, and even term is the square - 1 of term number
Number 10: 1 / (10 ^ 2-1) = 1 / 99

The number of a regular column: 5, 8, 11, 14, 17, 20 The tenth number in the list is______ The 100th number is________ The nth number is________

5,8,11,14,17,20…… The tenth number in the list is__ 32____ The 100th number is__ 302______ The nth number is__ 3n+2______

2, 5, 10, 17, 26 What is its 2005 number?

1 2 3 4 5
2 5 10 17 26
It's the square of each number plus 1
2005*2005=4020025+1=4020026

Press 2, 5, 10, 17, 26 The 2006 number

N²+1
2006²+1=4024037

A column of numbers 2,5,8,11,14,17 with obvious regularity. Where 2006 () a is the 668th number, B is the 669th number, and C is not in this column number

2+3n-3=2006
n=669
So choose B

Observe the number of columns: − 3 4，5 7，−9 10，17 13，−33 According to this rule, the next number is () A. 45 Twenty-one B. 45 Nineteen C. 65 Nineteen D. 65 Twenty-one

∵ the preceding symbol is (- 1) 6,
The next number is (- 1) 633 + 26 − 1
16+3=65
19，
Therefore, C