Math Problem Statement

Find the 64th term of the arithmetic sequence 2, comma, minus, 3, comma, minus, 8, comma, dot dot dot2,−3,−8,...

Solution

We are given the arithmetic sequence:

2,3,8,2, -3, -8, \dots

In an arithmetic sequence, the difference between consecutive terms is constant. This difference is called the common difference, denoted as dd.

Step 1: Find the common difference dd

To find dd, subtract the first term from the second term:

d=32=5d = -3 - 2 = -5

Thus, the common difference d=5d = -5.

Step 2: Use the formula for the nn-th term of an arithmetic sequence

The formula for the nn-th term of an arithmetic sequence is:

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

Where:

  • ana_n is the nn-th term,
  • a1a_1 is the first term,
  • dd is the common difference, and
  • nn is the term number.

Step 3: Find the 64th term

We are asked to find the 64th term, so set n=64n = 64, a1=2a_1 = 2, and d=5d = -5:

a64=2+(641)(5)a_{64} = 2 + (64 - 1) \cdot (-5) a64=2+63(5)a_{64} = 2 + 63 \cdot (-5) a64=2315a_{64} = 2 - 315 a64=313a_{64} = -313

Final Answer:

The 64th term of the sequence is 313\boxed{-313}.


Would you like further details on how I arrived at this solution, or do you have any other questions?

Here are some follow-up questions:

  1. How would the formula change if the sequence was a geometric sequence instead of an arithmetic one?
  2. How can you find the sum of the first nn terms of an arithmetic sequence?
  3. How can you use the common difference to predict future terms in the sequence?
  4. What happens if the common difference is positive instead of negative?
  5. Can you explain the concept of the "first term" in more detail?

Tip: When identifying the common difference in an arithmetic sequence, always subtract the first term from the second term (or any two consecutive terms) to find dd.

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Math Problem Analysis

Mathematical Concepts

Arithmetic Sequences
Linear Sequences
Common Difference

Formulas

a_n = a_1 + (n - 1) * d

Theorems

Arithmetic sequence formula

Suitable Grade Level

Grades 7-9