SOLUTION: someone please help me with this! ive tried a bunch of times and cant figure it out! write each sum using summation notation. Q1) 2 + 5 + 8 + 11 + ... + 29 Q2) 6 - 12 + 24

Algebra ->  Sequences-and-series -> SOLUTION: someone please help me with this! ive tried a bunch of times and cant figure it out! write each sum using summation notation. Q1) 2 + 5 + 8 + 11 + ... + 29 Q2) 6 - 12 + 24      Log On


   

Question 631818: someone please help me with this! ive tried a bunch of times and cant figure it out!
write each sum using summation notation.
Q1) 2 + 5 + 8 + 11 + ... + 29
Q2) 6 - 12 + 24 - 48 + ...

find the first 4 terms and the 8th term of the recursively-defined sequence.
Q1) c1 = 2, c2 = -1, and ck+2 = ck + ck+1 for k>0
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

General Summation Notation : sum%28+a%5Bn%5D%2C+n=1%2C+infinity+%29

{2 + 5 + 8 + 11 + ... + 29} Arithemetic, d = 3 a%5Bn%5D+=+2+%2B+%28n-1%293+=+3n-1

   sum%28+3n-1%2C+n=1%2C+10+%29



{6 - 12 + 24 - 48 + ...}  Geometric, r = (-2) a%5Bn%5D+=+6%28-2%29%5E%28n-1%29 

sum%286%2A%28-2%29%5E%28n-1%29%2C+n=1%2C+infinity%29



c%5B1%5D = 2, c%5B2%5D= -1, and c[k+2] = c%5Bk%5D + c[k+1] for k>0 

 { 2, -1, 1, 0, 1, 1, 2, 3 }  previous two terms added to get the next