/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 42 Determine all values of \(p\) fo... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Determine all values of \(p\) for which the series converges. $$\sum_{k=0}^{\infty} \frac{1}{(a+b k)^{p}}, a>0, b>0$$

Short Answer

Expert verified
The series \( \sum_{k=0}^{\infty} \frac{1}{(a+b k)^{p}} \) converges for the values of \( p > 1 \).

Step by step solution

01

Understanding the series

The series in question is a generalized p-series, which may be written as \( \sum_{k=0}^{\infty} \frac{1}{(a+b k)^{p}} \). It is given that \( a > 0 \) and \( b > 0 \) and \( k \) varies from 0 to infinity. The original form of a p-series is \( \sum_{n=1}^{\infty} \frac{1}{n^p} \). We should remember that a p-series converges if \( p > 1 \) and diverges if \( p \leq 1 \).
02

Applying the convergence criterion

We know that \( a > 0 \), \( b>0 \), thus \( a+bk > 0 \) for all \( k \). Hence, the series can have the form of a p-series with base replaced by \( a+bk \). As defined by the p-series convergence test for a standard p-series which states that a p-series \( \sum_{n=1}^{\infty} \frac{1}{n^p} \) converges if \( p > 1 \) and diverges if \( p \leq 1 \). We can apply this rule to our series.
03

Determine the p

Hence, for the series to converge, the exponent \( p \) should be greater than 1. Thus, the values of \( p \) for which the series converges are \( p > 1 \).

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.

Infinite Series
An infinite series is a sequence of numbers that are added together indefinitely. For example, the series \(1 + \frac{1}{2} + \frac{1}{3} + \frac{1}{4} + \cdots\) goes on forever. The concept of convergence is central to understanding infinite series. If the sum of an infinite series approaches a finite number as you add more and more terms, then the series 'converges' to that number.

In the context of the exercise, the infinite series is expressed as \( \sum_{k=0}^{\infty} \frac{1}{(a+bk)^{p}}\) where \(a\) and \(b\) are positive constants and \(p\) is an exponent. To grasp the behavior of such an infinite series, we rely on convergence tests to determine whether the series has a finite limit (converges) or not (diverges).
Convergence Tests
Convergence tests are tools that mathematicians use to determine whether an infinite series converges or diverges. These tests provide a systematic way to assess the behavior of series as more terms are added infinitely. One of the most fundamental convergence tests is the 'p-series test', which specifically assesses the convergence of series of the form \( \sum_{n=1}^{\infty} \frac{1}{n^p}\).

According to the p-series test, such a series will converge only if the exponent \( p > 1\). Conversely, if \( p \leq 1\), the series will diverge, meaning it will not sum to a finite value no matter how many terms are added. This test crucially relies on the exponent \(p\), demonstrating the importance of exponent rules in the analysis of series convergence.
Exponent Rules
Exponent rules are the guidelines determining how to handle operations involving exponents in mathematical expressions. They include laws for multiplying powers with the same base, dividing them, and raising powers to powers. In the context of infinite series and convergence tests, understanding exponent rules can clarify why a series behaves a certain way.

For example, when analyzing the series in the exercise \( \sum_{k=0}^{\infty} \frac{1}{(a+bk)^{p}}\), the exponent \( p \) governs the rate at which the series terms decrease. A larger value of \( p \) means each term will be a smaller contribution to the sum, making it more likely the series will converge. If \( p > 1\), the terms shrink rapidly enough to ensure convergence; this insight directly stems from applying exponent rules to understand the impact of \( p \) on the terms of the series.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The function \(\sin 8 \pi t\) represents a \(4-\mathrm{Hz}\) signal \((1 \mathrm{Hz} \text { equals } 1\) cycle per second) if \(t\) is measured in seconds. If you received this signal, your task might be to take your measurements of the signal and try to reconstruct the function. For example, if you measured three samples per second, you would have the data \(f(0)=0, f(1 / 3)=\sqrt{3} / 2, f(2 / 3)=-\sqrt{3} / 2\) and \(f(1)=0\) Knowing the signal is of the form \(A\) sin \(B t,\) you would use the data to try to solve for \(A\) and \(B\). In this case, you don't have enough information to guarantee getting the right values for A and \(B\). Prove this by finding several values of \(A\) and \(B\) with \(B \neq 8 \pi\) that match the data. A famous result of \(\mathrm{H}\). Nyquist from 1928 states that to reconstruct a signal of frequency \(f\) you need at least \(2 f\) samples.

If \(f\) is odd, show that \(g(x)=f(x) \cos x\) is odd and \(h(x)=f(x) \sin x\) is even. If \(f\) and \(g\) are even, what can you say about \(f g ?\)

Show that a power series representation of \(f(x)=\ln \left(1+x^{2}\right)\) is given by \(\sum_{k=0}^{\infty}(-1)^{k} \frac{x^{2 k+2}}{k+1} .\) For the partial sums \(P_{n}(x)=\sum_{k=0}^{n}(-1)^{k} \frac{x^{2 k+2}}{k+1}, \quad\) compute \(\quad\left|f(0.9)-P_{n}(0.9)\right|\) for each of \(n=2,4,6 .\) Discuss the pattern. Then compute \(\left|f(1.1)-P_{n}(1.1)\right|\) for each of \(n=2,4,6 .\) Discuss the pattern. Discuss the relevance of the radius of convergence to these calculations.

Use the Binomial Theorem to find the first five terms of the Maclaurin series. $$f(x)=\sqrt[3]{1+2 x}$$

Show that \(f(x)=\frac{x+1}{(1-x)^{2}}=\frac{\frac{2 x}{1-x}+1}{1-x}\) has the power series representation \(f(x)=1+3 x+5 x^{2}+7 x^{3}+9 x^{4}+\cdots\) Find the radius of convergence. Set \(x=\frac{1}{1000}\) and discuss the interesting decimal representation of \(\frac{1,001,000}{998,001}\)

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.