228k views
2 votes
How is the sum expressed in sigma notation?
1/64+1/16+1/4 + 1 + 4

User Willy
by
4.8k points

1 Answer

5 votes

9514 1404 393

Answer:

sum = ∑[n=1,5] 4^(n-4)

Explanation:

First of all, you need to be able to describe the n-th term.

Here, we have ...

term #: 1, 2, 3, 4, 5

value: 4^-3, 4^-2, 4^-1, 4^0, 4^1

That is, the exponent of 4 is 4 less than the term number. So, the n-th term is 4^(n-4). The sum of the 5 terms shown is then ...


\displaystyle sum=\sum_(n=1)^5{4^(n-4)}

User Simon Kuang
by
5.3k points