SOLUTION: Please help! I have been working on this problem night and I'm not going anywhere with it! Consider the sequence -7, -5.6, -4.2, -2.8,-1.4,... A. Write an explicit formula for t

Algebra ->  Sequences-and-series -> SOLUTION: Please help! I have been working on this problem night and I'm not going anywhere with it! Consider the sequence -7, -5.6, -4.2, -2.8,-1.4,... A. Write an explicit formula for t      Log On


   

Question 452871: Please help! I have been working on this problem night and I'm not going anywhere with it!
Consider the sequence -7, -5.6, -4.2, -2.8,-1.4,...
A. Write an explicit formula for the sequence (I know its An=A1+(n-1)d but I don't know where the 'D' comes from)
B. Write a recursive formula for the sequence.
C. Suppose you need to find the 50th term of the sequence. List which formula you should use.
D. Which term is the number 103.6
Sorry it's so much thats just all one number on my homework! please please help
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
A. a%5B1%5D+=+-7, d = 1.4
==> a%5Bn%5D+=+-7+%2B+%28n-1%291.4+=+-7+%2B+1.4n+-+1.4+=+1.4n+-+8.4
B. a%5Bn%2B1%5D+=+a%5Bn%5D+%2B+1.4

C. a%5B50%5D+=+1.4%2A50+-+8.4+=+61.6
D. 103.6+=+1.4n+-+8.4 ==> n = 80.