Chapter 15: Problem 6
(a) If \(C_{k}=p_{k} / q_{k}\) denotes the \(k\) th convergent of the finite simple continued fraction \([1 ; 2,3,4, \ldots, n, n+1]\), show that $$ p_{n}=n p_{n-1}+n p_{n-2}+(n-1) p_{n-3}+\cdots+3 p_{1}+2 p_{0}+\left(p_{0}+1\right) $$ [Hint: Add the relations \(p_{0}=1, p_{1}=3, p_{k}=(k+1) p_{k-1}+p_{k-2}\) for \(k=\) \(2, \ldots, n .]\) (b) Illustrate part (a) by calculating the numerator \(p_{4}\) for the fraction \([1 ; 2,3,4,5]\).
Short Answer
Step by step solution
Understanding the Initial Terms
Using the Recursive Formula
Applying the Formula for General \( n \)
Calculating Specific Terms for \(n=4\)
Verification of \( p_4 \) Using Sum Formula
Conclusion
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Recursive Sequences
Let's break this down:
- The term \( (k+1)p_{k-1} \) scales the previous numerator, \( p_{k-1} \), based on its position \( k \).
- The \( p_{k-2} \) term adds the second preceding numerator to ensure continuity and proper alignment with fraction expansion.
Convergents
Here’s the sequence:
- The first convergent uses the smallest terms and provides the simplest approximation.
- Subsequent convergents integrate more terms from the continued fraction, refining the approximation.
- Over time, as more terms are included, these convergents approach the true value of an irrational number more closely.
Number Theory
The relations given in the problem:
- Highlight properties of numbers that emerge from the interaction of predecessors.
- Showcases how these properties lead to the development of meaningful approximations.
- Offer insights into the predictability and beauty inherent within numerical structures.
Numerator Calculation
In the provided formula:
- The recursive formula \( p_k = (k+1)p_{k-1} + p_{k-2} \) sets the baseline for each numerator, leveraging the immediate predecessors to build forward.
- The series formula \( p_n = \sum_{i=0}^{n-1} (n-i)p_i + (p_0 + 1) \) encapsulates a global view of numerators, framing them as cumulative products of previous terms.