Math Problem Statement

Find the 15th term of an arithmetic sequence where the first term is 11 and the common difference is -7.

Solution

The image shows a question asking to find the 15th15^{\text{th}} term of an arithmetic sequence where the first term is 11 and the common difference is -7. The general formula for the nthn^{\text{th}} term of an arithmetic sequence is:

an=a1+(n1)da_n = a_1 + (n-1) \cdot d

Where:

  • ana_n is the nthn^{\text{th}} term,
  • a1a_1 is the first term,
  • nn is the term number, and
  • dd is the common difference.

Here, the first term a1=11a_1 = 11, the common difference d=7d = -7, and n=15n = 15. Plugging these values into the formula:

a15=11+(151)(7)a_{15} = 11 + (15-1) \cdot (-7)

Now let's calculate this.The 15th15^{\text{th}} term of the arithmetic sequence is 87-87.

Would you like more details or further clarification?

Here are 5 questions related to this:

  1. How do you derive the general formula for an arithmetic sequence?
  2. What happens to the terms of an arithmetic sequence when the common difference is negative?
  3. Can the nthn^{\text{th}} term formula be used to find the sum of the first nn terms?
  4. How does the value of nn affect the calculation in an arithmetic sequence?
  5. Can an arithmetic sequence ever have a common difference of zero?

Tip: In an arithmetic sequence, the common difference dd determines whether the sequence is increasing, decreasing, or constant.

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Math Problem Analysis

Mathematical Concepts

Arithmetic Sequences
Algebra

Formulas

nth term of an arithmetic sequence: a_n = a_1 + (n-1) * d

Theorems

General Formula for Arithmetic Sequences

Suitable Grade Level

Grades 7-9