SOLUTION: Geometric Progression.1. Consider the sequence 81,27,9,3. i. Find the 10th term of this sequence. ii. Find the sum of the first 10 terms of this sequence. iii. Consider the fi

Algebra ->  Customizable Word Problem Solvers  -> Finance -> SOLUTION: Geometric Progression.1. Consider the sequence 81,27,9,3. i. Find the 10th term of this sequence. ii. Find the sum of the first 10 terms of this sequence. iii. Consider the fi      Log On

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Question 988307: Geometric Progression.1. Consider the sequence 81,27,9,3.
i. Find the 10th term of this sequence.
ii. Find the sum of the first 10 terms of this sequence.
iii. Consider the first 20 terms of this sequence and find the sum of even number of terms.
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
These are decreasing powers of 3 starting with 3%5E4
a%5Bn%5D=3%5E%285-n%29
a%5B1%5D=3%5E4=81
a%5B2%5D=3%5E3=27
a%5B3%5D=3%5E2=9
a%5B4%5D=3%5E1=3
I)a%5B10%5D=3%5E%285-10%29=3%5E%28-5%29=1%2F243
II)
III)