Woo-Jin and Kiran were asked to find an explicit formula for the sequence 64,16,4,1,…, where the first term should be f(1).Woo-Jin said the formula is f(n)=64⋅(41)n, andKiran said the formula is f(n)=16⋅(41)n−1.Which one of them is right?Choose 1 answer:(A) Only Woo-Jin(B) Only Kiran(C) Both Woo-Jin and Kiran(D) Neither Woo-Jin nor Kiran
Q. Woo-Jin and Kiran were asked to find an explicit formula for the sequence 64,16,4,1,…, where the first term should be f(1).Woo-Jin said the formula is f(n)=64⋅(41)n, andKiran said the formula is f(n)=16⋅(41)n−1.Which one of them is right?Choose 1 answer:(A) Only Woo-Jin(B) Only Kiran(C) Both Woo-Jin and Kiran(D) Neither Woo-Jin nor Kiran
Question Prompt: The question prompt is: "Which formula correctly represents the sequence 64,16,4,1,…?"
Sequence Analysis: We have the sequence: 64,16,4,1,…This sequence is geometric because each term is obtained by multiplying the previous term by a common ratio.
Determine First Term and Common Ratio: Determine the first term f(1) and the common ratio r of the sequence.First term: f(1)=64To find the common ratio, divide the second term by the first term: r=6416=41
Check Woo-Jin's Formula: Now, let's check Woo-Jin's formula: f(n)=64×(41)nIf we substitute n=1, we get f(1)=64×(41)1=64×41=16, which is not the first term of the sequence. Therefore, Woo-Jin's formula is incorrect.
Check Kiran's Formula: Next, let's check Kiran's formula: f(n)=16×(41)(n−1) If we substitute n=1, we get f(1)=16×(41)(1−1)=16×(41)0=16×1=16, which is also not the first term of the sequence. Therefore, Kiran's formula is incorrect as well.
Find Correct Formula: Since both Woo-Jin and Kiran's formulas do not yield the correct first term when n=1, we need to find the correct formula. The correct formula should give us 64 when n=1.The correct formula is f(n)=64×(1/4)(n−1), which gives us f(1)=64×(1/4)(1−1)=64×(1/4)0=64×1=64.
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