Math Problem Statement

Find the 10th term of the sequence 2/3, 4/9, 8/27....

Solution

The given sequence is:

23,49,827,\frac{2}{3}, \frac{4}{9}, \frac{8}{27}, \dots

This is a geometric sequence where the first term a=23a = \frac{2}{3} and the common ratio rr is:

r=4923=49×32=23r = \frac{\frac{4}{9}}{\frac{2}{3}} = \frac{4}{9} \times \frac{3}{2} = \frac{2}{3}

The general formula for the nn-th term of a geometric sequence is:

an=arn1a_n = a \cdot r^{n-1}

Substituting the known values to find the 10th term:

a10=23(23)101=23(23)9a_{10} = \frac{2}{3} \cdot \left( \frac{2}{3} \right)^{10-1} = \frac{2}{3} \cdot \left( \frac{2}{3} \right)^9

Now let's compute:

a10=232939=210310a_{10} = \frac{2}{3} \cdot \frac{2^9}{3^9} = \frac{2^{10}}{3^{10}}

a10=102459049a_{10} = \frac{1024}{59049}

Thus, the 10th term of the sequence is:

102459049\frac{1024}{59049}

Would you like more details on any part of this solution?


Here are 5 related questions:

  1. How do you find the sum of the first nn terms of a geometric sequence?
  2. What is the common ratio in a geometric sequence?
  3. How do you determine if a sequence is arithmetic or geometric?
  4. Can geometric sequences have negative common ratios?
  5. How do you find the limit of a geometric sequence as nn \to \infty?

Tip: Always check for the common ratio by dividing consecutive terms when determining if a sequence is geometric.

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Math Problem Analysis

Mathematical Concepts

Geometric Sequences
Algebra

Formulas

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

Theorems

Geometric Sequence Theorem

Suitable Grade Level

Grades 9-12