Math Problem Statement

The first term of a sequence along with a recursion formula for the remaining terms is given below. Write out the first ten terms of the sequence. a 1 equals 5 comma a Subscript n plus 1 Baseline equals StartFraction na Subscript n Over n plus 3 EndFraction

Solution

Given the first term a1=5a_1 = 5 and the recursion formula:

an+1=nann+3a_{n+1} = \frac{n \cdot a_n}{n + 3}

we can find the first ten terms of the sequence by calculating each term based on the previous one.

Step-by-Step Calculation of Each Term

  1. First term: a1=5a_1 = 5
  2. Second term: a2=1a11+3=154=54=1.25a_2 = \frac{1 \cdot a_1}{1 + 3} = \frac{1 \cdot 5}{4} = \frac{5}{4} = 1.25
  3. Third term: a3=2a22+3=21.255=2.55=0.5a_3 = \frac{2 \cdot a_2}{2 + 3} = \frac{2 \cdot 1.25}{5} = \frac{2.5}{5} = 0.5
  4. Fourth term: a4=3a33+3=30.56=1.56=0.25a_4 = \frac{3 \cdot a_3}{3 + 3} = \frac{3 \cdot 0.5}{6} = \frac{1.5}{6} = 0.25
  5. Fifth term: a5=4a44+3=40.257=170.1429a_5 = \frac{4 \cdot a_4}{4 + 3} = \frac{4 \cdot 0.25}{7} = \frac{1}{7} \approx 0.1429
  6. Sixth term: a6=5a55+3=50.14298=0.714580.0893a_6 = \frac{5 \cdot a_5}{5 + 3} = \frac{5 \cdot 0.1429}{8} = \frac{0.7145}{8} \approx 0.0893
  7. Seventh term: a7=6a66+3=60.08939=0.535890.0595a_7 = \frac{6 \cdot a_6}{6 + 3} = \frac{6 \cdot 0.0893}{9} = \frac{0.5358}{9} \approx 0.0595
  8. Eighth term: a8=7a77+3=70.059510=0.4165100.0417a_8 = \frac{7 \cdot a_7}{7 + 3} = \frac{7 \cdot 0.0595}{10} = \frac{0.4165}{10} \approx 0.0417
  9. Ninth term: a9=8a88+3=80.041711=0.3336110.0303a_9 = \frac{8 \cdot a_8}{8 + 3} = \frac{8 \cdot 0.0417}{11} = \frac{0.3336}{11} \approx 0.0303
  10. Tenth term: a10=9a99+3=90.030312=0.2727120.0227a_{10} = \frac{9 \cdot a_9}{9 + 3} = \frac{9 \cdot 0.0303}{12} = \frac{0.2727}{12} \approx 0.0227

First Ten Terms of the Sequence

Thus, the first ten terms are approximately: 5,1.25,0.5,0.25,0.1429,0.0893,0.0595,0.0417,0.0303,0.02275, 1.25, 0.5, 0.25, 0.1429, 0.0893, 0.0595, 0.0417, 0.0303, 0.0227

Would you like more details or have any questions?


Related Questions:

  1. How does the recursion formula affect the behavior of this sequence as nn increases?
  2. What is the general behavior of the sequence in terms of convergence?
  3. How would the sequence change if the initial term a1a_1 were different?
  4. Can the recursive formula be expressed as a closed-form expression?
  5. How can this type of sequence be applied in real-world contexts?

Tip: Recurrence relations often lead to sequences that either converge, oscillate, or grow. Analyzing the recursion formula can give insights into the behavior of the sequence.

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Math Problem Analysis

Mathematical Concepts

Sequences
Recurrence Relations

Formulas

Recurrence relation: an+1 = (n * an) / (n + 3)

Theorems

Recursive Sequence Formula

Suitable Grade Level

Grades 9-12