Question

For the following geometric sequence, find the recursive formula. (-80, 20, -5, ...)

Answer 1

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Answer:

• a[1] = -80
• a[n] = -a[n-1]/4

Step-by-step explanation:

The first term is -80, so the first part of the recursive definition is ...

  a[1] = -80

The common ratio is 20/-80 = -1/4, so the recursive rule is ...

  a[n] = (-1/4)a[n-1]