Q. Find an explicit formula for the arithmetic sequence −31,−27,−23,−19,…..Note: the first term should be b(1).
b(n) = \(\square\)
Identify Type: Identify whether the given sequence is geometric or arithmetic. The sequence −31,−27,−23,−19,… has a common difference between consecutive terms, so it is an arithmetic sequence.
Use Formula: Use the explicit formula for an arithmetic sequence, bn=b1+(n−1)d, where b1 is the first term and d is the common difference. For the sequence −31,−27,−23,−19,…, the first term, b1, is −31 and the common difference, d, is 4 (since −27−(−31)=4).
Substitute Values: Substitute the values of b1 and d into the formula to write an expression to describe the sequence. The expression for the sequence −31,−27,−23,−19,… is bn=−31+(n−1)×4.
Simplify Expression: Simplify the expression to find the explicit formula. bn=−31+4n−4, which simplifies to bn=4n−35.
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