Math Problem Statement

Write the next three terms of the following sequence.

512, -256, 128, -64, . . .

Group of answer choices

-32, 16, and -8

128, -256, and 512

-128, 256, and -512

32, -16, and 8

Cannot be determined.

Solution

This sequence alternates between positive and negative terms, and it appears to follow a geometric progression where each term is multiplied by 12-\frac{1}{2} to get the next term.

Let's verify by dividing each consecutive term by the previous one:

256512=12\frac{-256}{512} = -\frac{1}{2} 128256=12\frac{128}{-256} = -\frac{1}{2} 64128=12\frac{-64}{128} = -\frac{1}{2}

Since the common ratio is 12-\frac{1}{2}, we can find the next three terms by multiplying the last term, 64-64, by 12-\frac{1}{2} repeatedly:

  1. 64×12=32-64 \times -\frac{1}{2} = 32
  2. 32×12=1632 \times -\frac{1}{2} = -16
  3. 16×12=8-16 \times -\frac{1}{2} = 8

Thus, the next three terms are: 32, -16, and 8.

The correct answer is: 32, -16, and 8.

Would you like further clarification or details on this sequence? Here are 5 related questions to expand your understanding:

  1. What is the general formula for the nth term of a geometric sequence?
  2. How do you determine the common ratio of a geometric sequence?
  3. Can a geometric sequence have a positive common ratio?
  4. How would the sequence change if the common ratio were positive?
  5. How do you determine the sum of an infinite geometric series?

Tip: In a geometric sequence, the ratio between consecutive terms remains constant.

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Math Problem Analysis

Mathematical Concepts

Sequences and Series
Geometric Progression
Negative Common Ratio

Formulas

nth term of a geometric sequence: a_n = a_1 * r^(n-1)

Theorems

Geometric progression theorem

Suitable Grade Level

Grades 8-10