Math Problem Statement

Find the 22nd term of the sequence: -2, -5, -8, -11, -14, ...

Solution

The sequence provided is 2,5,8,11,14,-2, -5, -8, -11, -14, \dots. This is an arithmetic sequence where the common difference dd between consecutive terms can be determined as:

d=5(2)=3d = -5 - (-2) = -3

The first term a1a_1 is 2-2. The formula for the nn-th term of an arithmetic sequence is:

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

We are tasked with finding the 22nd term (a22a_{22}):

a22=2+(221)(3)a_{22} = -2 + (22 - 1) \cdot (-3) a22=2+21(3)a_{22} = -2 + 21 \cdot (-3) a22=263a_{22} = -2 - 63 a22=65a_{22} = -65

Therefore, the 22nd term is 65-65.

Would you like further details or have any questions?

Here are 5 related questions:

  1. How do we derive the general formula for any arithmetic sequence?
  2. Can we find the sum of the first 22 terms in this sequence?
  3. What happens if the common difference was positive, how would the sequence change?
  4. How would you determine the number of terms if a specific value is known in the sequence?
  5. How does this formula apply if the sequence was geometric instead of arithmetic?

Tip: Always identify the common difference in an arithmetic sequence before proceeding to solve for any specific term.

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Math Problem Analysis

Mathematical Concepts

Arithmetic Sequence
Algebra

Formulas

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

Theorems

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Suitable Grade Level

Grades 7-9