SOLUTION: write an algebraic expression that represents Sn for each expression and find the ninth term of each sequence: 1.) {12,6,3,1.5,..} 2.) {1/2,1/3,1/4,1/5,..} 3.) {1,-2,3,-4,..}

Algebra ->  Sequences-and-series -> SOLUTION: write an algebraic expression that represents Sn for each expression and find the ninth term of each sequence: 1.) {12,6,3,1.5,..} 2.) {1/2,1/3,1/4,1/5,..} 3.) {1,-2,3,-4,..}      Log On


   



Question 387127: write an algebraic expression that represents Sn for each expression and find the ninth term of each sequence:
1.) {12,6,3,1.5,..}
2.) {1/2,1/3,1/4,1/5,..}
3.) {1,-2,3,-4,..}

Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
1. S_n = 12*(1/2)^n, S_9 = 12*(1/2)^9 = 3/128

2. S_n = 1/(n+1), S_9 = 1/10

3. S_n = -n[(-1)^n], S_9 = 9