Math Problem Statement

Find a2, a3, a4, and a5.

a1=55

an=–1/5an–1

Solution

To find a2a_2, a3a_3, a4a_4, and a5a_5 given the recursive formula:

a1=55a_1 = 55 an=15an1a_n = -\frac{1}{5} a_{n-1}

We will calculate each term step by step.


Step 1: Find a2a_2

a2=15a1=15×55=11a_2 = -\frac{1}{5} a_1 = -\frac{1}{5} \times 55 = -11


Step 2: Find a3a_3

a3=15a2=15×(11)=2.2a_3 = -\frac{1}{5} a_2 = -\frac{1}{5} \times (-11) = 2.2


Step 3: Find a4a_4

a4=15a3=15×2.2=0.44a_4 = -\frac{1}{5} a_3 = -\frac{1}{5} \times 2.2 = -0.44


Step 4: Find a5a_5

a5=15a4=15×(0.44)=0.088a_5 = -\frac{1}{5} a_4 = -\frac{1}{5} \times (-0.44) = 0.088


Final Results:

  • a2=11a_2 = -11
  • a3=2.2a_3 = 2.2
  • a4=0.44a_4 = -0.44
  • a5=0.088a_5 = 0.088

Would you like further explanation or details on the calculations?

Related Questions:

  1. What is the general formula for ana_n in this sequence?
  2. How do you determine if this sequence converges or diverges?
  3. What happens to the terms as nn increases indefinitely?
  4. How would the sequence change if a1a_1 were different?
  5. How can you graph this sequence?

Tip:

When dealing with geometric sequences involving negative ratios, pay attention to the alternating signs in the terms.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Sequences
Recursive Formulas
Arithmetic and Geometric Progressions

Formulas

Recursive Formula: an = -1/5 * an-1

Theorems

Properties of Geometric Sequences

Suitable Grade Level

Grades 9-12