In Exercises 61–68, use the graphs of and to find each indicated sum.

${\sum }_{i=4}^5(a_i/b_i{)}^2$

Verified step by step guidance

1. Identify the values of the sequences \(a_n\) and \(b_n\) for \(n = 4\) and \(n = 5\) from the graphs. For \(a_n\), locate the points at \(n=4\) and \(n=5\) on the first graph and note their corresponding \(a_n\) values. For \(b_n\), do the same on the second graph.
2. Write down the values explicitly: \(a_4\), \(a_5\), \(b_4\), and \(b_5\).
3. Calculate the ratio \(\frac{a_i}{b_i}\) for each \(i = 4, 5\). This means dividing the \(a_i\) value by the corresponding \(b_i\) value for each index.
4. Square each ratio to get \(\left(\frac{a_i}{b_i}\right)^2\) for \(i = 4, 5\).
5. Sum the squared ratios for \(i = 4\) and \(i = 5\) to find \(\sum_{i=4}^5 \left(\frac{a_i}{b_i}\right)^2\).

Key Concepts

Sequences and Terms

A sequence is an ordered list of numbers where each number is called a term, denoted as a_n or b_n. Understanding how to identify and interpret terms from a graph is essential, as each point corresponds to a term's value at a specific index n.

Summation Notation (Sigma Notation)

Summation notation, represented by the Greek letter Σ, is used to denote the sum of a sequence of terms. The expression Σ from i=4 to 5 means adding terms starting at i=4 up to i=5, which requires evaluating each term and then summing the results.

Operations on Sequences and Functions

This involves performing arithmetic operations on sequence terms, such as division and exponentiation. In this problem, each term a_i is divided by b_i, then squared, and finally summed. Understanding how to manipulate and combine sequence values is crucial.