Observe the following column: 1 / 2, - 1 / 6,1 / 12, - 1 / 20. Please find out the rule of arrangement and fill in the blanks according to the rule If n is an integer greater than 1, write the nth number according to the above arrangement
The denominator is 1 × 2, 2 × 3, 3 × 4... N × (n + 1)
Sign: positive and negative.. (- 1) ^ (n + 1)
law:
(-1)^ (n+1)/(n×(n+1))
RELATED INFORMATIONS
- 1. 1. Observe the following column number: - -. 2, 6, 12, 20. Please find out the rule of arrangement and fill in according to this rule 1 1 1 1 Look at the following number of columns: ---- 2 , 6 , 12 , 20 Please find out the rule of arrangement and fill in the blanks according to the rule (1) The ninth number is___ The fourteenth number is. (2) If n is an integer greater than 1, write the nth number according to the above arrangement
- 2. Observe the following column of numbers: 1 / 2, - 1 / 6,1 / 12, - 1 / 20. Please find out the rule and fill in the blanks according to the rule. The ninth number is ()
- 3. Look at the following sequence of numbers, one half minus one sixth minus one twelfth minus one twentieth... And so on, the ninth number is(
- 4. Look at the following column: half, one sixth, one twelfth, one twentieth And so on, what are the ninth and fourteenth numbers? Why?
- 5. The number of columns arranged according to a certain rule is negative half, one sixth, one twelfth, one twentieth and one thirtieth According to this rule, the 99th number is ()
- 6. One half, one sixth, one twelfth, one twentieth, one thirtieth The 60th number is ()
- 7. Observe the rules and fill in the blanks: 1 and 1 / 2, 2 and 1 / 4, 3 and 1 / 8 The nth number is(
- 8. There is a group of numbers: 1, 2, 5, 10, 17, 26,..., please observe the law of the composition of this group of numbers, and use the law you found to determine the eighth number as____ The nth number is ()
- 9. What are the rules of 1,2,5,10,17,26 1, 2, 5, 10, 17, 26. What's the rule
- 10. There is a column of numbers 7, O, 2,5,3,7,0,2,5,3. What is the 19th number and the 28th number
- 11. A series of numbers arranged regularly are: 2, 3, 10, 15, 26, 35 According to this rule, what is the seventh number in this column?
- 12. There is a column of numbers, which are arranged into 1, - 2,4, - 8,16, - 32 according to a certain rule, in which the appropriate number of three adjacent numbers is - 96, what are the three numbers?
- 13. The number of columns in regular order: 2, - 4, 8, - 16, 32, - 64 The sum of some four adjacent numbers is - 640. What is the difference between the largest number and the smallest number?
- 14. The number of columns in regular order: 2, - 4, 8, - 16, 32, - 64 The sum of some four adjacent numbers is - 640. What is the difference between the largest number and the smallest number?
- 15. The number of columns in regular order: 2, - 4, 8, - 16, 32, - 64 The sum of some four adjacent numbers is - 640. What is the difference between the largest number and the smallest number?
- 16. The number of columns in regular order: 2, - 4, 8, - 16, 32, - 64 The sum of some four adjacent numbers is - 640. What is the difference between the largest number and the smallest number?
- 17. 1. 4 times the sum of a and 9 () 2. 30 less than 5 times of X () 3. The sum of X and Y divided by their difference () 4. The sum of a and its reciprocal () 5. The square of the sum of M and n ()
- 18. There is a group of numbers: 1 * 2,2 * 3,3 * 4, ··········································································
- 19. Eighth grade mathematics: when the letters in the following formula meet what conditions, the fraction is meaningful~~~ 1. 2/a 2. x+1/x-1 3. 2m /3m+2 4. 1/x-y 5 2a+b/3a-b 6. 2/x-2 It's a process! Because of what, so what form
- 20. A series of numbers are arranged according to the following rules: 1, 2, 3, 2, 3, 4, 3, 4, 5, 4, 5, 5, 6, 6, 7 Ask for detailed explanation