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)
Identify Geometric Pattern: We observe that each term in the sequence is the previous term divided by 4. This suggests that the sequence is geometric with the first term a=64 and the common ratio r=41.
Find Explicit Formula: To find the explicit formula for a geometric sequence, we use the formula f(n)=a⋅r(n−1), where a is the first term, r is the common ratio, and n is the term number.
Substitute Values: Substitute the values of a and r into the formula to get f(n)=64×(41)(n−1).
Simplify Formula: We can simplify the formula by noting that 64 is 43, so we can write the formula as f(n)=43×(41)(n−1).
Apply Exponent Property: Using the property of exponents that (am)n=am∗n, we can simplify the formula further to f(n)=43−n+1.
Final Explicit Formula: Simplify the exponent to get the final explicit formula: f(n)=44−n.
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