Q. Write an explicit formula for an, the nth term of the sequence 1,−4,16,…Answer: an=
Identify Pattern: Identify the pattern in the sequence.The given sequence is 1,−4,16,…We notice that each term is multiplied by −4 to get the next term.This indicates that the sequence is geometric.
Determine Terms: Determine the first term a1 and the common ratio r of the sequence.The first term, a1=1To find the common ratio, r, we divide the second term by the first term:r=−4/1=−4
Write Formula: Write the explicit formula for the nth term of a geometric sequence.The formula for the nth term of a geometric sequence is:an=a1⋅r(n−1)Substitute the values of a1 and r into the formula:an=1⋅(−4)(n−1)
Simplify: Simplify the formula.The simplified formula for the nth term is:an=(−4)n−1
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