Q. What kind of sequence is this?69,49,29,9,…Choices:(A) arithmetic(B) geometric(C) both(D) neither
Verify Consecutive Differences: Let's verify if the differences between consecutive terms are uniform. Given sequence: 69,49,29,9,… Are the consecutive differences in the sequence equal? 49−69=−20, 29−49=−20, 9−29=−20. The consecutive differences in the sequence are equal.
Identify Arithmetic Sequence: Since the consecutive differences are equal, this indicates that the sequence is an arithmetic sequence. An arithmetic sequence is defined by having a common difference between consecutive terms.
Check for Geometric Sequence: Now, let's check if the sequence could also be geometric by finding the ratios between consecutive terms. Given sequence: 69,49,29,9,… Are the ratios between consecutive terms in the sequence equal? 6949≈0.7101, 4929≈0.5918, 299≈0.3103. The ratios are not equal, so the sequence is not geometric.
Final Conclusion: Since the sequence has a common difference but not a common ratio, it is an arithmetic sequence and not a geometric sequence. Therefore, the correct choice is (A) arithmetic.
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