Math Problem Statement

1. В геометрической прогрессии (bn) известно, что b1 = 2, q = -2. Найти пятый член этой прогрессии.

Solution

This image contains a set of problems on geometric progressions. Let's go through the first one:

  1. In the geometric progression (bn)(b_n), it is known that b1=2b_1 = 2 and q=2q = -2. Find the fifth term of this progression.

The general formula for the nn-th term of a geometric progression is:
bn=b1qn1b_n = b_1 \cdot q^{n-1} Substituting the given values: b5=2(2)4=216=32b_5 = 2 \cdot (-2)^{4} = 2 \cdot 16 = 32 So, the fifth term is b5=32b_5 = 32.

Would you like a detailed explanation for this solution or help with another problem?

Here are some follow-up questions to expand on the topic:

  1. How do you find the sum of the first nn terms of a geometric progression?
  2. What happens if the common ratio qq is a fraction?
  3. How can you determine if a sequence is geometric?
  4. What are the applications of geometric progressions in real life?
  5. How does changing the first term affect the progression?

Tip: When solving geometric progressions, always check the sign of the common ratio qq as it influences the pattern of the terms.

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Math Problem Analysis

Mathematical Concepts

Geometric Progression
Sequences
Exponentiation

Formulas

b_n = b_1 * q^(n-1)

Theorems

Geometric Progression Formula

Suitable Grade Level

Grades 7-9