Question

Is -3,12,-48... a arithmetic or geometric formula

Answer 1

Answer:

  geometric sequence

Step-by-step explanation:

A list of 3 numbers is not a "formula". It is a "sequence."

The differences between the numbers are ...

  12 -(-3) = 15

  -48 -12 = -60

These are not constant, so the sequence is not arithmetic.

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The ratios between the numbers are ...

  12/-3 = -4

  -48/12 = -4

These are constant, so the sequence is geometric.

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The formula for the n-th term of a geometric sequence is ...

  an = a1·r^(n-1)

We have first term a1 = -3 and common ratio r = -4. So, the formula for this sequence is ...

  an = -3(-4)^(n-1)