Math Problem Statement

What is 10th term of geometric sequence 8,4,2,1,...?

Solution

To find the 10th term of a geometric sequence, you can use the formula:

an=a1×r(n1)a_n = a_1 \times r^{(n-1)}

where:

  • ana_n is the nn-th term of the sequence,
  • a1a_1 is the first term,
  • rr is the common ratio,
  • nn is the term number.

Given:

  • a1=8a_1 = 8,
  • The common ratio r=48=12r = \frac{4}{8} = \frac{1}{2},
  • n=10n = 10.

Now, plug in the values:

a10=8×(12)(101)=8×(12)9=8×1512=8512=164a_{10} = 8 \times \left(\frac{1}{2}\right)^{(10-1)} = 8 \times \left(\frac{1}{2}\right)^9 = 8 \times \frac{1}{512} = \frac{8}{512} = \frac{1}{64}

So, the 10th term of the sequence is 164\frac{1}{64}.

Would you like further details or have any questions?

Here are some related questions:

  1. How do you find the common ratio in a geometric sequence?
  2. What is the sum of the first 10 terms of this geometric sequence?
  3. How do you determine if a sequence is arithmetic or geometric?
  4. What is the general formula for the sum of an infinite geometric series?
  5. How does changing the common ratio affect the sequence?

Tip: In a geometric sequence, if the common ratio is a fraction between 0 and 1, the terms will get smaller as the sequence progresses.

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Math Problem Analysis

Mathematical Concepts

Geometric Sequences

Formulas

Geometric sequence formula: a_n = a_1 * r^(n-1)

Theorems

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Suitable Grade Level

Grades 9-12