1-3, - 2-5,3-35, - 4-63, the nth number is____________________ (find the rules)
If the second number is - 2 / 15, it's easy to do
The molecule is 1, 2, 3, 4 The order of
The denominator is: 1 * 3,3 * 5,5 * 7,7 * 9
[(-1)^(n+1)]n/[(2n-1)(2n+1)]
RELATED INFORMATIONS
- 1. Find the law of mathematics 1 3 5 7 15 () ()
- 2. Find the rules 1: Twenty five, (), thirty, (), forty five 2:( ),( ),( ),63,( ),( ),( ),89,( )
- 3. A question about finding laws in mathematics? When I are 1,2,3 and s are 5,3,1, what is the relationship between I and S?
- 4. 4,6,10,16,()()()
- 5. A problem of finding rules in junior high school mathematics 1,4, - 9,16,25, - 36,49,64, - 81. What is the nth number Notice that every three numbers have a minus sign,
- 6. A group of numbers in regular order: 2,0,4,0,6,0, ·, in which the seventh number is (), and the nth number is ()
- 7. According to the rule of 1, 8, 27, 64,..., the sixth number should be (); according to the rule of 2, 5, 8, 11, 14,..., the number of 83 should be () The () th in this column
- 8. Arrange 1, 2, 3, 4. Into the following matrix according to certain rules: 1 2 5 10. 4 3 6 11. 9 8 7 12 . 16 15 14 13. .... So, what's the number in row 3 (from top to bottom) and column 6 (from left to right)?
- 9. Observe the numbers in each column in the following order, fill in the following two numbers according to the rule, and write the 55th and 100th numbers. (1) - 2,4, - 6,8, - 10,12_____ ,_____ , 55th number (), 100th number () [2] 1, - 1,1, - 1,1, - 1 -, -. 55th number (), 100th number ()
- 10. Here is a regular array of triangles First line: 1 The second line 1 Third line: 1 2 1 The fourth line: 1 3 3 1 The fifth line: 1 4 6 4 1 The sixth line; 1 5 10 10 5 1 . What is the third number from the left of line 1997 Not only the answer, but also the method,
- 11. 1 / 3, - 2 / 15, 3 / 35, - 4 / 63
- 12. -2, - 8,4, - 20,28, - 68... Find the rules,
- 13. Fill in the number 2 10 4 15 6 20 8 () thank you
- 14. Find the law 1 / 2 - (3 / 10), 5 / 26 - (7 / 50),. Find the 10th number
- 15. Please fill in the n-th number in the brackets: 1, 3, 6, 10, 15, () 10,20,40,80,() 1,-2,3,-4,5,-6()
- 16. 21 / 32,1,25 / 24,17 / 18,43 / 54, () sequence reasoning
- 17. Seeking sequence: 0,6, - 6,18, - 30,66 General term formula
- 18. The general formula of 2,6,10,14,18,22,26,30 RT
- 19. Write a general term formula of the sequence so that the first four terms are 1,4,10,22... (write the verification process)
- 20. 6, 9, 13, 18. The general formula of this sequence