Chapter 8-Infinite Series Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons,...

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Chapter 8-Infinite Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Chapter 8-Infinite Series8.1 Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Definition of an Infinite Series

Chapter 8-Infinite Series8.1 Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Definition of an Infinite Series

Chapter 8-Infinite Series8.1 Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Convergence of Infinite Series

Chapter 8-Infinite Series8.1 Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

A Telescoping Series

Chapter 8-Infinite Series8.1 Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Harmonic Series

Chapter 8-Infinite Series8.1 Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Basic Properties of Series

Chapter 8-Infinite Series8.1 Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Basic Properties of Series

Chapter 8-Infinite Series8.1 Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Series of Powers (Geometric Series)

Chapter 8-Infinite Series8.1 Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Series of Powers (Geometric Series)

EXAMPLE: At a certain aluminum recycling plant, the recycling process turns n pounds of used aluminum into 9n/10 pounds of new aluminum. Including the initial quantity, how much usable aluminum will 100 pounds of virgin aluminum ultimately yield, if we assume that it is continually returned to the same recycling plant?

Chapter 8-Infinite Series8.1 Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Quick Quiz

1. Which of the numbers 9/8, 10/8, 11/8, 12/8, is a partial sum of

2. True or false: The sum of two convergent series is also convergent.

3. What is the value of

4. Does converge or diverge?

Chapter 8-Infinite Series8.2 The Divergence Test and The Integral Test

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Divergence Test

EXAMPLE: What does the Divergence Test tell us about the geometric series What about the series ?

Chapter 8-Infinite Series8.2 The Divergence Test and The Integral Test

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Series with Nonnegative Terms

EXAMPLE: Discuss convergence for the series

Chapter 8-Infinite Series8.2 The Divergence Test and The Integral Test

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Integral Test

THEOREM: Let f be a positive, continuous, decreasing function on the interval [1,). Thenthe infinite series converges if and only if the improper integral converges.

Chapter 8-Infinite Series8.2 The Divergence Test and The Integral Test

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Integral Test

EXAMPLE: Show the following series converges and estimate its value

EXAMPLE: Show the following series converges and estimate its value .

Chapter 8-Infinite Series8.2 The Divergence Test and The Integral Test

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

p-series

THEOREM: Fix a real number p. The series

converges if p>1 and diverges if p≤1.

EXAMPLE: Determine whether the following series is convergent

Chapter 8-Infinite Series8.2 The Divergence Test and The Integral Test

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Quick Quiz

Chapter 8-Infinite Series8.3 The Comparison Test

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Comparison Test for Convergence

Chapter 8-Infinite Series8.3 The Comparison Test

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Comparison Test for Convergence

EXAMPLE: For each of the following, determine whether the series converges or diverges.

Chapter 8-Infinite Series8.3 The Comparison Test

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Limit Comparison Test

Chapter 8-Infinite Series8.3 The Comparison Test

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Quick Quiz

Chapter 8-Infinite Series8.4 Alternating Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Alternating Series Test

Chapter 8-Infinite Series8.4 Alternating Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Alternating Series Test

EXAMPLE: Analyze the series

EXAMPLE: Show that the following series converges

Chapter 8-Infinite Series8.4 Alternating Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Absolute Convergence

THEOREM: If a series converges absolutely, then it converges.

Chapter 8-Infinite Series8.4 Alternating Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Absolute Convergence

EXAMPLE: Does the following series converge?

Chapter 8-Infinite Series8.4 Alternating Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Absolute Convergence

Chapter 8-Infinite Series8.4 Alternating Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Conditional Convergence

Chapter 8-Infinite Series8.4 Alternating Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Quick Quiz

Chapter 8-Infinite Series8.5 The Ratio and Root Tests

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Ratio Test

Chapter 8-Infinite Series8.5 The Ratio and Root Tests

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Ratio Test

EXAMPLE: Apply the ratio test to the following

Chapter 8-Infinite Series8.5 The Ratio and Root Tests

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Root Test

Chapter 8-Infinite Series8.5 The Ratio and Root Tests

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Root Test

EXAMPLE: Apply the ratio test to the following

Chapter 8-Infinite Series8.5 The Ratio and Root Tests

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Quick Quiz

Chapter 8-Infinite Series8.6 Introduction to Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Chapter 8-Infinite Series8.6 Introduction to Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

EXAMPLE: Which of the following are power series in x?

Chapter 8-Infinite Series8.6 Introduction to Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Radius and Interval of Convergence

THEOREM: Let be a power series. Then precisely one of the following statements holds:

a) The series converges absolutely for every real x;b) There is a positive number R such that the series converges absolutely for |x| < R and diverges for|x| > R;c) The series converges only at x = 0.

Chapter 8-Infinite Series8.6 Introduction to Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Radius and Interval of Convergence

Chapter 8-Infinite Series8.6 Introduction to Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Radius and Interval of Convergence

Chapter 8-Infinite Series8.6 Introduction to Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Radius and Interval of Convergence

Chapter 8-Infinite Series8.6 Introduction to Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Radius and Interval of Convergence

Chapter 8-Infinite Series8.6 Introduction to Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Power Series about an Arbitrary Base Point

Chapter 8-Infinite Series8.6 Introduction to Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Power Series about an Arbitrary Base Point

Chapter 8-Infinite Series8.6 Introduction to Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Power Series about an Arbitrary Base Point

EXAMPLE: Determine the interval of convergence for the following series.

Chapter 8-Infinite Series8.6 Introduction to Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Addition and Scalar Multiplication of Power Series

Chapter 8-Infinite Series8.6 Introduction to Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Differentiation and Antidifferentiation of Power Series

Chapter 8-Infinite Series8.6 Introduction to Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Differentiation and Antidifferentiation of Power Series

EXAMPLE: Calculate the derivative and the indefinite integral of the power series below for x in the interval of convergence I=(-1,1).

Chapter 8-Infinite Series8.6 Introduction to Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Quick Quiz

Chapter 8-Infinite Series8.7 Representing Functions by Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Power Series Expansions of Some Standard Functions

Chapter 8-Infinite Series8.7 Representing Functions by Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Power Series Expansions of Some Standard Functions

EXAMPLE: Express the following as a power series with base point 0.

EXAMPLE: Find a power series representation for the function F(x)=ln(1+x).

Chapter 8-Infinite Series8.7 Representing Functions by Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Relationship between the Coefficients and Derivatives

Chapter 8-Infinite Series8.7 Representing Functions by Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

The Relationship between the Coefficients and Derivatives

Chapter 8-Infinite Series8.7 Representing Functions by Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

An Application to Differential Equations

EXAMPLE: Find a power series solution of the initial value problem dy/dx=y-x, y(0)=2.

Chapter 8-Infinite Series8.7 Representing Functions by Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Taylor Series and Polynomials

DEFINITION: If a function f is N times continuously differentiable on a interval containing c, then

is called the Taylor polynomial of order N and base point c for the function f. If f is infinitely differentiable, then we have a Taylor series.

Chapter 8-Infinite Series8.7 Representing Functions by Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Taylor Series and Polynomials

THEOREM: Suppose that f is N times continuously differentiable. Then

TN(c)=f(c), TN’(c)=f’(c), TN’’(c)=f’’(c), …, TN(N)(c)=f(N)(c)

EXAMPLE: Compute the Taylor polynomials of order one, two, and three for the function f(x)=e2x expanded with base point c=0.

Chapter 8-Infinite Series8.7 Representing Functions by Power Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Quick Quiz

Chapter 8-Infinite Series8.8 Taylor Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Taylor’s Theorem

f(x) = TN(x) + RN(x)THEOREM: For any natural number N, suppose that f is N + 1 times continuously differentiableon an open interval I centered at c. If x is a point in I, then there is a number s between c and x such that

Chapter 8-Infinite Series8.8 Taylor Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Taylor’s Theorem

EXAMPLE: Calculate the order 7 Taylor polynomial T7 (x) with base point 0 of sin (x). If T7 (x) is used to approximate sin (x) for −1 ≤ x ≤ 1, what accuracy is guaranteed by Taylor’s Theorem?

Chapter 8-Infinite Series8.8 Taylor Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Estimating the Error TermTHEOREM: Let f be a function that is N + 1 times continuously differentiable on an open interval I centered at c. For each x in I let Jx denote the closed interval with endpoints x and c. Thus, Jx = [c, x] if c ≤ x and Jx = [x, c] if x < c. Let

Then the error term RN(x) satisfies

Chapter 8-Infinite Series8.8 Taylor Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Estimating the Error Term

EXAMPLE: Use the third order Taylor polynomial of ex with base point 0 to approximate e-0.1. Estimate your accuracy.

Chapter 8-Infinite Series8.8 Taylor Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Achieving a Desired Degree of Accuracy

EXAMPLE: Compute ln(1.2) to an accuracy of four decimals places.

Chapter 8-Infinite Series8.8 Taylor Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Taylor Series Expansions of the Common Transcendental Functions

THEOREM: Suppose that f is infinitely differentiable on an interval containing points c and x. Then

exists if and only limN RN(x) exists, and

If and only if

Chapter 8-Infinite Series8.8 Taylor Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Taylor Series Expansions of the Common Transcendental Functions

EXAMPLE: Show that

EXAMPLE: Show that

Chapter 8-Infinite Series8.8 Taylor Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Using Taylor Series to Approximate

Chapter 8-Infinite Series8.8 Taylor Series

Calculus, 2ed, by Blank & Krantz, Copyright 2011 by John Wiley & Sons, Inc, All Rights Reserved

Quick Quiz