SOLUTION: what is the deriving rule of -5,-2,1,4

Algebra ->  Sequences-and-series -> SOLUTION: what is the deriving rule of -5,-2,1,4      Log On


   

Question 1084777: what is the deriving rule of -5,-2,1,4
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!

Recursive rule:

Begin with -5, add 3 each time to get the next term
  -5 + 3 = -2
  -2 + 3 =  1
   1 + 3 =  4
   4 + 3 =  7
   7 + 3 = 10
   ...

General rule:

Deriving by formula:

a%5Bn%5D=a%5B1%5D%2B%28n-1%29d
a%5Bn%5D=-5%2B%28n-1%293
a%5Bn%5D=-5%2B3%28n-1%29
a%5Bn%5D=-5%2B3n-3
a%5Bn%5D=3n-8

Multiply each counting number by 3 and subtract 8

3(1) - 8 =  3 - 8 = -5
3(2) - 8 =  6 - 8 = -2
3(3) - 8 =  9 - 8 =  1
3(4) - 8 = 12 - 8 =  4
3(5) - 8 = 15 - 8 =  7
3(6) - 8 = 18 - 8 = 10
...

Edwin