Q. Find an explicit formula for the geometric sequence −25,−50,−100,−200,…. Note: the first term should be d(1).d(n)=
Identify sequence type: Identify the type of sequence.The sequence is −25, −50, −100, −200, extellipsis Each term is obtained by multiplying the previous term by a common ratio.This is a geometric sequence.
Determine first term and common ratio: Determine the first term d(1) and the common ratio r.The first term d(1) is −25.To find the common ratio, divide the second term by the first term: r=−25−50=2.
Write explicit formula for geometric sequence: Write the explicit formula for the geometric sequence using d(1) and r. The explicit formula for a geometric sequence is d(n)=d(1)⋅r(n−1). Substitute d(1)=−25 and r=2 into the formula. d(n)=−25⋅2(n−1).
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