Which recursive sequence would produce the sequence 7,−33,167,… ?a1=7 and an=2an−1−5a1=7 and an=−5an−1+2a1=7 and an=−4an−1−5a1=7 and an=−5an−1−4
Q. Which recursive sequence would produce the sequence 7,−33,167,… ?a1=7 and an=2an−1−5a1=7 and an=−5an−1+2a1=7 and an=−4an−1−5a1=7 and an=−5an−1−4
Identify First Term: Identify the first term of the sequence.The first term given is a1=7.
Test First Formula: Use the second term to test the recursive formulas.The second term in the sequence is −33. We will substitute n=2 into each recursive formula to see which one yields −33 when the first term is 7.For the first formula:a2=2a1−5a2=2(7)−5a2=14−5a2=9This does not match the second term of the sequence, which is −33.
Test Second Formula: Test the second recursive formula.For the second formula:a2=−5a1+2a2=−5(7)+2a2=−35+2a2=−33This matches the second term of the sequence.
Verify Third Term: Verify the third term using the correct formula from Step 3.The third term in the sequence is 167. We will now check if this term can be obtained by applying the recursive formula an=−5an−1+2 with n=3.a3=−5a2+2a3=−5(−33)+2a3=165+2a3=167This matches the third term of the sequence.
Conclude Correct Formula: Conclude that the correct recursive formula is found.Since the recursive formula an=−5an−1+2 produces the correct second and third terms of the sequence when starting with a1=7, we can conclude that this is the correct recursive formula for the given sequence.
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