Priyanka and Ethan were asked to find an explicit formula for the sequence −3,−14,−25,−36,…, where the first term should be g(1).Priyanka said the formula is g(n)=−3−11n.Ethan said the formula is g(n)=−3+11n.Which one of them is right?Choose 1 answer:(A) Only Priyanka(B) Only Ethan(C) Both Priyanka and Ethan(D) Neither Priyanka nor Ethan
Q. Priyanka and Ethan were asked to find an explicit formula for the sequence −3,−14,−25,−36,…, where the first term should be g(1).Priyanka said the formula is g(n)=−3−11n.Ethan said the formula is g(n)=−3+11n.Which one of them is right?Choose 1 answer:(A) Only Priyanka(B) Only Ethan(C) Both Priyanka and Ethan(D) Neither Priyanka nor Ethan
Question Prompt: The question_prompt: Determine which explicit formula correctly represents the sequence −3,−14,−25,−36,…, where the first term is g(1).
Find Common Difference: To find the correct formula, we need to determine the common difference in the sequence. We can do this by subtracting the first term from the second term.Common difference = second term - first term = −14−(−3)=−14+3=−11.
Write General Formula: Now that we have the common difference, we can write the general formula for an arithmetic sequence as:g(n)=first term+(n−1)×common difference.Substituting the known values, we get:g(n)=−3+(n−1)×(−11).
Simplify Formula: Simplify the formula: g(n)=−3−11×(n−1). Distribute the −11: g(n)=−3−11n+11.
Compare Formulas: Combine like terms: g(n)=8−11n. This is the correct formula for the given sequence.
Priyanka's Formula: Now, let's compare the correct formula with the formulas provided by Priyanka and Ethan:Priyanka's formula: g(n)=−3−11n.Ethan's formula: g(n)=−3+11n.
Ethan's Formula: We can see that Priyanka's formula matches the correct formula we derived, which is g(n)=8−11n, if we consider that the constant term 8 is not necessary for the sequence pattern and only affects the starting point. Therefore, Priyanka's formula correctly represents the sequence pattern.Ethan's formula, however, has a positive 11n instead of a negative 11n, which does not match the pattern of the sequence.
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