Q. Which word best describes this formula for the sequence an?an=−4an−1+5an−4+19n+3Choices:(A)explicit(B)recursive
Examine Formula: Look at the formula: an=−4an−1+5an−4+19n+3. Does it use previous terms of the sequence? Yes, it uses an−1 and an−4, which are earlier terms in the sequence.
Use of Previous Terms: Since the formula for an depends on previous terms of the sequence, it's not explicit. An explicit formula would directly calculate an based on n alone.
Explicit vs. Recursive: The formula is recursive because it defines each term using previous terms in the sequence.So, the correct choice is (B) recursive.
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