Gustavo and Yuki were asked to find an explicit formula for the sequence 19,0,−19,−38,…, where the first term should be h(1).Gustavo said the formula is h(n)=19−19n.Yuki said the formula is h(n)=−19+19n.Which one of them is right?Choose 1 answer:(A) Only Gustavo(B) Only Yuki(C) Both Gustavo and Yuki(D) Neither Gustavo nor Yuki
Q. Gustavo and Yuki were asked to find an explicit formula for the sequence 19,0,−19,−38,…, where the first term should be h(1).Gustavo said the formula is h(n)=19−19n.Yuki said the formula is h(n)=−19+19n.Which one of them is right?Choose 1 answer:(A) Only Gustavo(B) Only Yuki(C) Both Gustavo and Yuki(D) Neither Gustavo nor Yuki
Identify pattern in sequence: Identify the pattern in the sequence. The sequence 19, 0, −19, −38, ... decreases by 19 each time. This indicates that it is an arithmetic sequence with a common difference of −19.
Determine first term: Determine the first term of the sequence. The first term, h(1), is 19.
Use explicit formula: Use the explicit formula for an arithmetic sequence, h(n)=h(1)+(n−1)d, where h(1) is the first term and d is the common difference. For this sequence, h(1)=19 and d=−19.
Substitute values into formula: Substitute the values of h(1) and d into the formula to find the explicit formula for the sequence. The formula becomes h(n)=19+(n−1)(−19).
Simplify the formula: Simplify the formula. h(n)=19−19(n−1)=19−19n+19=19(1−n)=19−19n.
Compare with Gustavo and Yuki: Compare the simplified formula to the formulas provided by Gustavo and Yuki. Gustavo's formula is h(n)=19−19n, which matches our derived formula. Yuki's formula is h(n)=−19+19n, which does not match our derived formula.
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