• Home
  • Textbooks
  • Algebra and Trigonometry Real Mathematics, Real People
  • Sequences, Series, and Probability

Algebra and Trigonometry Real Mathematics, Real People

Ron Larson

Chapter 9

Sequences, Series, and Probability - all with Video Answers

Educators

AG

Section 1

Sequences and Series

00:17

Problem 1

Fill in the blank(s).
The function values $a_{1}, a_{2}, a_{3}, a_{4}, \ldots, a_{n}, \ldots$ are called the _____ of a sequence.

AG
Ankit Gupta
Numerade Educator
00:21

Problem 2

Fill in the blank(s).
If you are given one or more of the first few terms of a sequence, and all other terms of the sequence are defined using previous terms, then the sequence is defined _____.

AG
Ankit Gupta
Numerade Educator
00:34

Problem 3

Fill in the blank(s).
For the sum $\sum_{i=1}^{n} a_{i}, i$ is called the _____ of summation, $n$ is the _____ of summation, and 1 is the _____ of summation.

AG
Ankit Gupta
Numerade Educator
00:11

Problem 4

Fill in the blank(s).
The sum of the terms of a finite or an infinite sequence is called a _____.

AG
Ankit Gupta
Numerade Educator
00:30

Problem 5

Which describes an infinite sequence? a finite sequence?
(a) The domain consists of the first $n$ positive integers.
(b) The domain consists of the set of positive integers.

AG
Ankit Gupta
Numerade Educator
00:18

Problem 6

Write $1 \cdot 2 \cdot 3 \cdot 4 \cdot 5 \cdot 6$ in factorial notation.

AG
Ankit Gupta
Numerade Educator
01:24

Problem 7

Write the first five terms of the sequence. (Assume $n$ begins with 1.)
$$a_{n}=2 n-5$$

AG
Ankit Gupta
Numerade Educator
01:28

Problem 8

Write the first five terms of the sequence. (Assume $n$ begins with 1.)
$$a_{n}=4 n-7$$

AG
Ankit Gupta
Numerade Educator
01:08

Problem 9

Write the first five terms of the sequence. (Assume $n$ begins with 1.)
$$a_{n}=3^{n}$$

AG
Ankit Gupta
Numerade Educator
01:53

Problem 10

Write the first five terms of the sequence. (Assume $n$ begins with 1.)
$$a_{n}=\left(\frac{1}{2}\right)^{n}$$

AG
Ankit Gupta
Numerade Educator
01:46

Problem 11

Write the first five terms of the sequence. (Assume $n$ begins with 1.)
$$a_{n}=\left(-\frac{1}{2}\right)^{n}$$

AG
Ankit Gupta
Numerade Educator
01:14

Problem 12

Write the first five terms of the sequence. (Assume $n$ begins with 1.)
$$a_{n}=(-2)^{n}$$

AG
Ankit Gupta
Numerade Educator
01:11

Problem 13

Write the first five terms of the sequence. (Assume $n$ begins with 1.)
$$a_{n}=\frac{n+1}{n}$$

AG
Ankit Gupta
Numerade Educator
01:13

Problem 14

Write the first five terms of the sequence. (Assume $n$ begins with 1.)
$$a_{n}=\frac{n}{n+1}$$

AG
Ankit Gupta
Numerade Educator
01:28

Problem 15

Write the first five terms of the sequence. (Assume $n$ begins with 1.)
$$a_{n}=\frac{n}{n^{2}+1}$$

AG
Ankit Gupta
Numerade Educator
01:49

Problem 16

Write the first five terms of the sequence. (Assume $n$ begins with 1.)
$$a_{n}=\frac{2 n}{n+1}$$

AG
Ankit Gupta
Numerade Educator
01:41

Problem 17

Write the first five terms of the sequence (a) using the table feature of a graphing utility and (b) algebraically. (Assume $n$ begins with 1.) $$a_{n}=\frac{1+(-1)^{n}}{n}$$

AG
Ankit Gupta
Numerade Educator
01:53

Problem 18

Write the first five terms of the sequence (a) using the table feature of a graphing utility and (b) algebraically. (Assume $n$ begins with 1.) $$a_{n}=\frac{1+(-1)^{n}}{2 n}$$

AG
Ankit Gupta
Numerade Educator
01:32

Problem 19

Write the first five terms of the sequence (a) using the table feature of a graphing utility and (b) algebraically. (Assume $n$ begins with 1.) $$a_{n}=1-\frac{1}{2^{n}}$$

AG
Ankit Gupta
Numerade Educator
01:49

Problem 20

Write the first five terms of the sequence (a) using the table feature of a graphing utility and (b) algebraically. (Assume $n$ begins with 1.) $$a_{n}=\frac{3^{n}}{4^{n}}$$

AG
Ankit Gupta
Numerade Educator
01:48

Problem 21

Write the first five terms of the sequence (a) using the table feature of a graphing utility and (b) algebraically. (Assume $n$ begins with 1.) $$a_{n}=\frac{1}{n^{3 / 2}}$$

AG
Ankit Gupta
Numerade Educator
01:21

Problem 22

Write the first five terms of the sequence (a) using the table feature of a graphing utility and (b) algebraically. (Assume $n$ begins with 1.) $$a_{n}=\frac{1}{\sqrt{n}}$$

AG
Ankit Gupta
Numerade Educator
01:41

Problem 23

Write the first five terms of the sequence (a) using the table feature of a graphing utility and (b) algebraically. (Assume $n$ begins with 1.) $$a_{n}=\frac{(-1)^{n}}{n^{2}}$$

AG
Ankit Gupta
Numerade Educator
01:49

Problem 24

Write the first five terms of the sequence (a) using the table feature of a graphing utility and (b) algebraically. (Assume $n$ begins with 1.) $$a_{n}=(-1)^{n}\left(\frac{n}{n+1}\right)$$

AG
Ankit Gupta
Numerade Educator
01:47

Problem 25

Write the first five terms of the sequence (a) using the table feature of a graphing utility and (b) algebraically. (Assume $n$ begins with 1.) $$a_{n}=(2 n-1)(2 n+1)$$

AG
Ankit Gupta
Numerade Educator
01:22

Problem 26

Write the first five terms of the sequence (a) using the table feature of a graphing utility and (b) algebraically. (Assume $n$ begins with 1.) $$a_{n}=n(n-1)(n-2)$$

AG
Ankit Gupta
Numerade Educator
02:41

Problem 27

Use the table feature of a graphing utility to find the first 10 terms of the sequences. (Assume $n$ begins with 1.)
$$a_{n}=2(3 n-1)+5$$

AG
Ankit Gupta
Numerade Educator
02:24

Problem 28

Use the table feature of a graphing utility to find the first 10 terms of the sequences. (Assume $n$ begins with 1.)
$$a_{n}=2 n(n+1)-7$$

AG
Ankit Gupta
Numerade Educator
02:16

Problem 29

Use the table feature of a graphing utility to find the first 10 terms of the sequences. (Assume $n$ begins with 1.)
$$a_{n}=1+\frac{n+1}{n}$$

AG
Ankit Gupta
Numerade Educator
02:56

Problem 30

Use the table feature of a graphing utility to find the first 10 terms of the sequences. (Assume $n$ begins with 1.)
$$a_{n}=\frac{4 n^{2}}{n+2}$$

AG
Ankit Gupta
Numerade Educator
01:26

Problem 31

Use the table feature of a graphing utility to find the first 10 terms of the sequences. (Assume $n$ begins with 1.)
$$a_{n}=(-1)^{n}+1$$

AG
Ankit Gupta
Numerade Educator
01:26

Problem 32

Use the table feature of a graphing utility to find the first 10 terms of the sequences. (Assume $n$ begins with 1.)
$$a_{n}=(-1)^{n+1}+8$$

AG
Ankit Gupta
Numerade Educator
00:38

Problem 33

Find the indicated term of the sequence.
$$\begin{aligned}
&a_{n}=\frac{n^{2}}{n^{2}+1}\\
&a_{10}=
\end{aligned}$$

AG
Ankit Gupta
Numerade Educator
00:41

Problem 34

Find the indicated term of the sequence.
$$\begin{aligned}
&a_{n}=\frac{n^{2}}{2 n+1}\\
&a_{5}=
\end{aligned}$$

AG
Ankit Gupta
Numerade Educator
01:09

Problem 35

Find the indicated term of the sequence.
$$\begin{aligned}
&a_{n}=(-1)^{n}(3 n-2)\\
&a_{25}=
\end{aligned}$$

AG
Ankit Gupta
Numerade Educator
01:18

Problem 36

Find the indicated term of the sequence.
$$\begin{aligned}
&a_{n}=(-1)^{n-1}[n(n-1)]\\
&a_{16}=
\end{aligned}$$

AG
Ankit Gupta
Numerade Educator
00:50

Problem 37

Find the indicated term of the sequence.
$$\begin{aligned}
&a_{n}=\frac{2^{n+1}}{2^{n}+1}\\
&a_{7}=
\end{aligned}$$

AG
Ankit Gupta
Numerade Educator
00:49

Problem 38

Find the indicated term of the sequence.
$$\begin{aligned}
&a_{n}=\frac{3^{n}}{3^{n}+1}\\
&a_{6}=
\end{aligned}$$

AG
Ankit Gupta
Numerade Educator
02:14

Problem 39

Write an expression for the apparent $n$ th term of the sequence. (Assume $n$ begins with $1 .$)
$$3,8,13,18,23, \dots$$

AG
Ankit Gupta
Numerade Educator
02:31

Problem 40

Write an expression for the apparent $n$ th term of the sequence. (Assume $n$ begins with $1 .$)
$$3,7,11,15,19, \ldots$$

AG
Ankit Gupta
Numerade Educator
01:56

Problem 41

Write an expression for the apparent $n$ th term of the sequence. (Assume $n$ begins with $1 .$)
$$7,13,19,25,31, \ldots$$

AG
Ankit Gupta
Numerade Educator
01:58

Problem 42

Write an expression for the apparent $n$ th term of the sequence. (Assume $n$ begins with $1 .$)
$$9,11,13,15,17, \ldots$$

AG
Ankit Gupta
Numerade Educator
01:23

Problem 43

Write an expression for the apparent $n$ th term of the sequence. (Assume $n$ begins with $1 .$)
$$0,3,8,15,24, \ldots$$

AG
Ankit Gupta
Numerade Educator
03:09

Problem 44

Write an expression for the apparent $n$ th term of the sequence. (Assume $n$ begins with $1 .$)
$$4,7,12,19,28, \dots$$

AG
Ankit Gupta
Numerade Educator
00:42

Problem 45

Write an expression for the apparent $n$ th term of the sequence. (Assume $n$ begins with $1 .$)
$$\frac{2}{3}, \frac{3}{4}, \frac{4}{5}, \frac{5}{6}, \frac{6}{7}, \dots$$

AG
Ankit Gupta
Numerade Educator
01:05

Problem 46

Write an expression for the apparent $n$ th term of the sequence. (Assume $n$ begins with $1 .$)
$$\frac{2}{1}, \frac{3}{3}, \frac{4}{5}, \frac{5}{7}, \frac{6}{9}, \dots$$

AG
Ankit Gupta
Numerade Educator
02:00

Problem 47

Write an expression for the apparent $n$ th term of the sequence. (Assume $n$ begins with $1 .$)
$$\frac{1}{2}, \frac{-1}{4}, \frac{1}{8}, \frac{-1}{16}, \dots$$

AG
Ankit Gupta
Numerade Educator
01:54

Problem 48

Write an expression for the apparent $n$ th term of the sequence. (Assume $n$ begins with $1 .$)
$$\frac{1}{3},-\frac{2}{9}, \frac{4}{27},-\frac{8}{81}, \dots$$

AG
Ankit Gupta
Numerade Educator
01:06

Problem 49

$$1+\frac{1}{1}, 1+\frac{1}{2}, 1+\frac{1}{3}, 1+\frac{1}{4}, 1+\frac{1}{5}, \dots$$$$1+\frac{1}{1}, 1+\frac{1}{2}, 1+\frac{1}{3}, 1+\frac{1}{4}, 1+\frac{1}{5}, \dots$$

AG
Ankit Gupta
Numerade Educator
01:17

Problem 50

Write an expression for the apparent $n$ th term of the sequence. (Assume $n$ begins with $1 .$)
$$1+\frac{1}{3}, 1+\frac{1}{6}, 1+\frac{1}{11}, 1+\frac{1}{18}, 1+\frac{1}{27}, \ldots$$

AG
Ankit Gupta
Numerade Educator
01:22

Problem 51

Write an expression for the apparent $n$ th term of the sequence. (Assume $n$ begins with $1 .$)
$$1,3,1,3,1, . . .$$

AG
Ankit Gupta
Numerade Educator
00:56

Problem 52

Write an expression for the apparent $n$ th term of the sequence. (Assume $n$ begins with $1 .$)
$$1,-1,1,-1,1, \ldots$$

AG
Ankit Gupta
Numerade Educator
01:50

Problem 53

Write the first five terms of the sequence defined recursively.
$$a_{1}=28, a_{k}=a_{k-1}-4$$

AG
Ankit Gupta
Numerade Educator
01:47

Problem 54

Write the first five terms of the sequence defined recursively.
$$a_{1}=15, a_{k}=a_{k-1}+3$$

AG
Ankit Gupta
Numerade Educator
01:37

Problem 55

Write the first five terms of the sequence defined recursively.
$$a_{1}=3, a_{k+1}=2\left(a_{k}-1\right)$$

AG
Ankit Gupta
Numerade Educator
01:29

Problem 56

Write the first five terms of the sequence defined recursively.
$$a_{1}=32, a_{k+1}=\frac{1}{2} a_{k}$$

AG
Ankit Gupta
Numerade Educator
02:13

Problem 57

Write the first five terms of the sequence defined recursively.
$$a_{0}=1, a_{1}=3, a_{k}=a_{k-2}+a_{k-1}$$

AG
Ankit Gupta
Numerade Educator
01:33

Problem 58

Write the first five terms of the sequence defined recursively.
$$a_{0}=-1, a_{1}=5, a_{k}=a_{k-2}+a_{k-1}$$

AG
Ankit Gupta
Numerade Educator
02:30

Problem 59

Write the first five terms of the sequence defined recursively. Use the pattern to write the $n$ th term of the sequence as a function of $n .$ (Assume $n$ begins with 1.)
$$a_{1}=6, a_{k+1}=a_{k}+2$$

AG
Ankit Gupta
Numerade Educator
02:16

Problem 60

Write the first five terms of the sequence defined recursively. Use the pattern to write the $n$ th term of the sequence as a function of $n .$ (Assume $n$ begins with 1.)
$$a_{1}=25, a_{k+1}=a_{k}-5$$

AG
Ankit Gupta
Numerade Educator
02:13

Problem 61

Write the first five terms of the sequence defined recursively. Use the pattern to write the $n$ th term of the sequence as a function of $n .$ (Assume $n$ begins with 1.)
$$a_{1}=81, a_{k+1}=\frac{1}{3} a_{k}$$

AG
Ankit Gupta
Numerade Educator
02:29

Problem 62

Write the first five terms of the sequence defined recursively. Use the pattern to write the $n$ th term of the sequence as a function of $n .$ (Assume $n$ begins with 1.)
$$a_{1}=14, a_{k+1}=-2 a_{k}$$

AG
Ankit Gupta
Numerade Educator
02:12

Problem 63

Write the first five terms of the sequence
(a) using the table feature of a graphing utility and
(b) algebraically. (Assume $n$ begins with 0.)
$$a_{n}=\frac{1}{n !}$$

AG
Ankit Gupta
Numerade Educator
02:23

Problem 64

Write the first five terms of the sequence
(a) using the table feature of a graphing utility and
(b) algebraically. (Assume $n$ begins with 0.)
$$a_{n}=\frac{1}{(n+1) !}$$

AG
Ankit Gupta
Numerade Educator
02:43

Problem 65

Write the first five terms of the sequence
(a) using the table feature of a graphing utility and
(b) algebraically. (Assume $n$ begins with 0.)
$$a_{n}=\frac{n^{2}}{(n+1) !}$$

AG
Ankit Gupta
Numerade Educator
02:41

Problem 66

Write the first five terms of the sequence
(a) using the table feature of a graphing utility and
(b) algebraically. (Assume $n$ begins with 0.)
$$a_{n}=\frac{n^{3}}{(n+2) !}$$

AG
Ankit Gupta
Numerade Educator
03:00

Problem 67

Write the first five terms of the sequence
(a) using the table feature of a graphing utility and
(b) algebraically. (Assume $n$ begins with 0.)
$$a_{n}=\frac{(-1)^{2 n}}{(2 n) !}$$

AG
Ankit Gupta
Numerade Educator
03:42

Problem 68

Write the first five terms of the sequence
(a) using the table feature of a graphing utility and
(b) algebraically. (Assume $n$ begins with 0.)
$$a_{n}=\frac{(-1)^{2 n+1}}{(2 n+1) !}$$

AG
Ankit Gupta
Numerade Educator
00:40

Problem 69

Simplify the factorial expression.
$$\frac{2 !}{4 !}$$

AG
Ankit Gupta
Numerade Educator
00:36

Problem 70

Simplify the factorial expression.
$$\frac{5 !}{7 !}$$

AG
Ankit Gupta
Numerade Educator
01:01

Problem 71

Simplify the factorial expression.
$$\frac{12 !}{4 ! \cdot 8 !}$$

AG
Ankit Gupta
Numerade Educator
01:04

Problem 72

Simplify the factorial expression.
$$\frac{10 !}{5 ! \cdot 3 !}$$

AG
Ankit Gupta
Numerade Educator
01:03

Problem 73

Simplify the factorial expression.
$$\frac{(n+3) !}{n !}$$

AG
Ankit Gupta
Numerade Educator
00:45

Problem 74

Simplify the factorial expression.
$$\frac{(n+2) !}{n !}$$

AG
Ankit Gupta
Numerade Educator
01:12

Problem 75

Simplify the factorial expression.
$$\frac{(2 n-1) !}{(2 n+1) !}$$

AG
Ankit Gupta
Numerade Educator
01:06

Problem 76

Simplify the factorial expression.
$$\frac{(2 n-2) !}{(2 n) !}$$

AG
Ankit Gupta
Numerade Educator
02:15

Problem 77

Match the sequence with its graph. [The graphs are Iabeled (a), (b), (c), and (d).]
$$a_{n}=\frac{8}{n+1}$$

AG
Ankit Gupta
Numerade Educator
02:41

Problem 78

Match the sequence with its graph. [The graphs are Iabeled (a), (b), (c), and (d).]
$$a_{n}=\frac{8 n}{n+1}$$

AG
Ankit Gupta
Numerade Educator
02:16

Problem 79

Match the sequence with its graph. [The graphs are Iabeled (a), (b), (c), and (d).]
$$a_{n}=\frac{2^{n+2}}{2 n !}$$

AG
Ankit Gupta
Numerade Educator
02:46

Problem 80

Match the sequence with its graph. [The graphs are Iabeled (a), (b), (c), and (d).]
$$a_{n}=\frac{4^{n}}{n !}$$

AG
Ankit Gupta
Numerade Educator
01:03

Problem 81

Use a graphing utility to graph the first 10 terms of the sequence. (Assume $n$ begins with 1.)
$$a_{n}=\frac{2}{3} n$$

AG
Ankit Gupta
Numerade Educator
00:46

Problem 82

Use a graphing utility to graph the first 10 terms of the sequence. (Assume $n$ begins with 1.)
$$a_{n}=\frac{1}{2} n+3$$

AG
Ankit Gupta
Numerade Educator
00:55

Problem 83

Use a graphing utility to graph the first 10 terms of the sequence. (Assume $n$ begins with 1.)
$$a_{n}=16(-0.5)^{n-1}$$

AG
Ankit Gupta
Numerade Educator
00:50

Problem 84

Use a graphing utility to graph the first 10 terms of the sequence. (Assume $n$ begins with 1.)
$$a_{n}=8(-0.75)^{n-1}$$

AG
Ankit Gupta
Numerade Educator
00:51

Problem 85

Use a graphing utility to graph the first 10 terms of the sequence. (Assume $n$ begins with 1.)
$$a_{n}=\frac{2 n}{n+1}$$

AG
Ankit Gupta
Numerade Educator
00:52

Problem 86

Use a graphing utility to graph the first 10 terms of the sequence. (Assume $n$ begins with 1.)
$$a_{n}=\frac{3 n^{2}}{n^{2}+1}$$

AG
Ankit Gupta
Numerade Educator
01:15

Problem 87

Find the sum.
$$\sum_{i=1}^{5}(2 i+1)$$

AG
Ankit Gupta
Numerade Educator
01:09

Problem 88

Find the sum.
$$\sum_{i=1}^{6}(3 i-1)$$

AG
Ankit Gupta
Numerade Educator
00:54

Problem 89

Find the sum.
$$\sum_{i=0}^{6} 4 i^{2}$$

AG
Ankit Gupta
Numerade Educator
00:49

Problem 90

Find the sum.
$$\sum_{i=0}^{5} 3 i^{2}$$

AG
Ankit Gupta
Numerade Educator
02:20

Problem 91

Find the sum.
$$\sum_{j=3}^{5} \frac{1}{j^{2}-3}$$

AG
Ankit Gupta
Numerade Educator
01:34

Problem 92

Find the sum.
$$\sum_{j=3}^{5} \frac{1}{j+1}$$

AG
Ankit Gupta
Numerade Educator
01:29

Problem 93

Find the sum.
$$\sum_{k=1}^{4} 10$$

AG
Ankit Gupta
Numerade Educator
01:32

Problem 94

Find the sum.
$$\sum_{k=1}^{5} 4$$

AG
Ankit Gupta
Numerade Educator
02:06

Problem 95

Find the sum.
$$\sum_{i=2}^{5}\left[(i-1)^{3}+(i+1)^{2}\right]$$

AG
Ankit Gupta
Numerade Educator
02:48

Problem 96

Find the sum.
$$\sum_{k=2}^{7}\left[(k+1)+(k-3)^{2}\right]$$

AG
Ankit Gupta
Numerade Educator
01:22

Problem 97

Find the sum.
$$\sum_{i=0}^{4} 2^{i}$$

AG
Ankit Gupta
Numerade Educator
01:34

Problem 98

Find the sum.
$$\sum_{j=0}^{4}(-2)^{j}$$

AG
Ankit Gupta
Numerade Educator
00:25

Problem 99

Use a graphing utility to find the sum.
$$\sum_{j=1}^{6}(24-3 j)$$

AG
Ankit Gupta
Numerade Educator
00:25

Problem 100

Use a graphing utility to find the sum.
$$\sum_{j=1}^{10} \frac{6}{3 j+1}$$

AG
Ankit Gupta
Numerade Educator
00:49

Problem 101

Use a graphing utility to find the sum.
$$\sum_{k=0}^{4} \frac{(-1)^{k}}{(k+1) !}$$

AG
Ankit Gupta
Numerade Educator
00:54

Problem 102

Use a graphing utility to find the sum.
$$\sum_{k=0}^{4} \frac{(-1)^{k}}{k !}$$

AG
Ankit Gupta
Numerade Educator
01:34

Problem 103

Use sigma notation to write the sum. Then use a graphing utility to find the sum.
$$\frac{1}{3(1)}+\frac{1}{3(2)}+\frac{1}{3(3)}+\cdots+\frac{1}{3(9)}$$

AG
Ankit Gupta
Numerade Educator
01:41

Problem 104

Use sigma notation to write the sum. Then use a graphing utility to find the sum.
$$\frac{5}{1+1}+\frac{5}{1+2}+\frac{5}{1+3}+\cdots+\frac{5}{1+15}$$

AG
Ankit Gupta
Numerade Educator
01:49

Problem 105

Use sigma notation to write the sum. Then use a graphing utility to find the sum.
$$\left[2\left(\frac{1}{8}\right)+3\right]+\left[2\left(\frac{2}{8}\right)+3\right]+\cdots+\left[2\left(\frac{8}{8}\right)+3\right]$$

AG
Ankit Gupta
Numerade Educator
00:56

Problem 106

Use sigma notation to write the sum. Then use a graphing utility to find the sum.
$$\left[1-\left(\frac{1}{6}\right)^{2}\right]+\left[1-\left(\frac{2}{6}\right)^{2}\right]+\cdots+\left[1-\left(\frac{6}{6}\right)^{2}\right]$$

AG
Ankit Gupta
Numerade Educator
01:57

Problem 107

Use sigma notation to write the sum. Then use a graphing utility to find the sum.
$$-3+9-27+81-243+729$$

AG
Ankit Gupta
Numerade Educator
01:43

Problem 108

Use sigma notation to write the sum. Then use a graphing utility to find the sum.
$$1-\frac{1}{2}+\frac{1}{4}-\frac{1}{8}+\cdot \cdot \cdot-\frac{1}{128}$$

AG
Ankit Gupta
Numerade Educator
01:23

Problem 109

Use sigma notation to write the sum. Then use a graphing utility to find the sum.
$$\frac{1}{1^{2}}-\frac{1}{2^{2}}+\frac{1}{3^{2}}-\frac{1}{4^{2}}+\cdots \cdot-\frac{1}{20^{2}}$$

AG
Ankit Gupta
Numerade Educator
01:16

Problem 110

Use sigma notation to write the sum. Then use a graphing utility to find the sum.
$$\frac{1}{1 \cdot 3}-\frac{1}{2 \cdot 4}+\frac{1}{3 \cdot 5}-\frac{1}{4 \cdot 6}+\cdot \cdot \cdot-\frac{1}{10 \cdot 12}$$

AG
Ankit Gupta
Numerade Educator
03:12

Problem 111

Use sigma notation to write the sum. Then use a graphing utility to find the sum.
$$\frac{1}{4}+\frac{3}{8}+\frac{7}{16}+\frac{15}{32}+\frac{31}{64}$$

AG
Ankit Gupta
Numerade Educator
01:41

Problem 112

Use sigma notation to write the sum. Then use a graphing utility to find the sum.
$$\frac{1}{2}+\frac{2}{4}+\frac{6}{8}+\frac{24}{16}+\frac{120}{32}+\frac{720}{64}$$

AG
Ankit Gupta
Numerade Educator
01:45

Problem 113

Find the indicated partial sum of the series.
$\sum_{i=1}^{\infty} \frac{7}{5^{i}}$
Fourth partial sum

AG
Ankit Gupta
Numerade Educator
01:49

Problem 114

Find the indicated partial sum of the series.
$\sum_{i=1}^{\infty} \frac{2}{3^{i}}$
Fifth partial sum

AG
Ankit Gupta
Numerade Educator
01:18

Problem 115

Find the indicated partial sum of the series.
$\sum_{n=1}^{\infty} 4\left(-\frac{1}{2}\right)^{n}$
Third partial sum

AG
Ankit Gupta
Numerade Educator
01:45

Problem 116

Find the indicated partial sum of the series.
$\sum_{n=1}^{\infty} 8\left(-\frac{1}{4}\right)^{n}$
Fourth partial sum

AG
Ankit Gupta
Numerade Educator
02:30

Problem 117

Find (a) the fourth partial sum and (b) the sum of the infinite series.
$$\sum_{i=1}^{\infty} \frac{6}{10^{i}}$$

AG
Ankit Gupta
Numerade Educator
02:59

Problem 118

Find (a) the fourth partial sum and (b) the sum of the infinite series.
$$\sum_{k=1}^{\infty} \frac{4}{10^{k}}$$

AG
Ankit Gupta
Numerade Educator
02:40

Problem 119

Find (a) the fourth partial sum and (b) the sum of the infinite series.
$$\sum_{k=1}^{\infty} 7\left(\frac{1}{10}\right)^{k}$$

AG
Ankit Gupta
Numerade Educator
02:12

Problem 120

Find (a) the fourth partial sum and (b) the sum of the infinite series.
$$\sum_{i=1}^{\infty} 2\left(\frac{1}{10}\right)^{i}$$

AG
Ankit Gupta
Numerade Educator
02:24

Problem 121

A deposit of $5000$dollar is made in an account that earns $3 \%$ interest compounded quarterly. The balance in the account after $n$ quarters is given by $$A_{n}=5000\left(1+\frac{0.03}{4}\right)^{n}, \quad n=1,2,3, \ldots$$
(a) Compute the first eight terms of this sequence.
(b) Find the balance in this account after 10 years by computing the $40$th term of the sequence.

AG
Ankit Gupta
Numerade Educator
04:00

Problem 122

An investor deposits $10,000$dollar in an account that earns $3.5 \%$ interest compounded monthly. The balance in the account after $n$ months is given by $$A_{n}=10,000\left(1+\frac{0.035}{12}\right)^{n}, \quad n=1,2,3, . . .$$
(a) Write the first eight terms of the sequence.
(b) Find the balance in the account after 5 years by computing the 60 th term of the sequence.
(c) Is the balance after 10 years twice the balance after 5 years? Explain.

AG
Ankit Gupta
Numerade Educator
03:03

Problem 123

A landlocked lake has been selected to be stocked in the year 2015 with 5500 trout, and to be restocked each year thereafter with 500 trout. Each year the fish population declines $25 \%$ due to harvesting and other natural causes.
(a) Write a recursive sequence that gives the population $p_{n}$ of trout in the lake in terms of the year $n,$ with $n=0$ corresponding to 2015.
(b) Use the recursion formula from part (a) to find the numbers of trout in the lake for $n=1,2,3$ and $4 .$ Interpret these values in the context of the situation.
(c) Use a graphing utility to find the number of trout in the lake as time passes infinitely. Explain your result.

AG
Ankit Gupta
Numerade Educator
04:25

Problem 124

The revenues $R_{n}$ (in millions of dollars) of Netflix from 2008 through 2013 are shown in the table. (Source: Netflix, Inc.)
(a) Use a graphing utility to graph the data. Let $n$ represent the year, with $n=8$ corresponding to 2008.
(b) Use the regression feature of the graphing utility to find a linear sequence and a quadratic sequence that model the data. Identify the coefficient of determination for each model.
(c) Graph each model with the data. Decide which model is a better fit for the data. Explain.
(d) Use the model you chose in part (c) to predict the revenue of Netflix in $2017 .$ Does your answer seem reasonable? Explain.
(e) Use your model from part (c) to find when the revenue will reach 15 billion dollars.
(f) Use the model you chose in part (c) to approximate the total revenue from 2008 through 2013 . Compare this sum with the result of adding the revenues shown in the table.

AG
Ankit Gupta
Numerade Educator
00:18

Problem 125

Determine whether the statement is true or false. Justify your answer.
$$\sum_{i=1}^{4}\left(i^{2}+2 i\right)=\sum_{i=1}^{4} i^{2}+2 \sum_{i=1}^{4} i$$

AG
Ankit Gupta
Numerade Educator
00:16

Problem 126

Determine whether the statement is true or false. Justify your answer.
$$\sum_{j=1}^{4} 2^{j}=\sum_{j=3}^{6} 2^{j-2}$$

AG
Ankit Gupta
Numerade Educator
01:28

Problem 127

Use the Fibonacci sequence. (See Example 5.)
Write the first 12 terms of the Fibonacci sequence $a_{n}$ and the first 10 terms of the sequence given by
$$b_{n}=\frac{a_{n+1}}{a_{n}}, \quad n>0$$.

AG
Ankit Gupta
Numerade Educator
00:49

Problem 128

Use the Fibonacci sequence. (See Example 5.)
Using the definition of $b_{n}$ given in Exercise $127,$ show that $b_{n}$ can be defined recursively by
$$b_{n}=1+\frac{1}{b_{n-1}}$$.

AG
Ankit Gupta
Numerade Educator
00:39

Problem 129

Let $$a_{n}=\frac{(1+\sqrt{5})^{n}-(1-\sqrt{5})^{n}}{2^{n} \sqrt{5}}$$ be a sequence with $n$ th term $a_{n}$.
Use the table feature of a graphing utility to find the first five terms of the sequence.

AG
Ankit Gupta
Numerade Educator
00:20

Problem 130

Let $$a_{n}=\frac{(1+\sqrt{5})^{n}-(1-\sqrt{5})^{n}}{2^{n} \sqrt{5}}$$ be a sequence with $n$ th term $a_{n}$.
Do you recognize the terms of the sequence in Exercise $129 ?$ What sequence is it?

AG
Ankit Gupta
Numerade Educator
00:53

Problem 131

Let $$a_{n}=\frac{(1+\sqrt{5})^{n}-(1-\sqrt{5})^{n}}{2^{n} \sqrt{5}}$$ be a sequence with $n$ th term $a_{n}$.
Find expressions for $a_{n+1}$ and $a_{n+2}$ in terms of $n$.

AG
Ankit Gupta
Numerade Educator
00:54

Problem 132

Let $$a_{n}=\frac{(1+\sqrt{5})^{n}-(1-\sqrt{5})^{n}}{2^{n} \sqrt{5}}$$ be a sequence with $n$ th term $a_{n}$.
Use the result from Exercise 131 to show that $a_{n+2}=a_{n+1}+a_{n} .$ Is this result the same as your answer to Exercise $129 ?$ Explain.

AG
Ankit Gupta
Numerade Educator
00:25

Problem 133

Write the first five terms of the sequence.
$$a_{n}=\frac{x^{n}}{n !}$$

AG
Ankit Gupta
Numerade Educator
00:43

Problem 134

Write the first five terms of the sequence.
$$a_{n}=\frac{x^{2}}{n^{2}}$$

AG
Ankit Gupta
Numerade Educator
00:44

Problem 135

Write the first five terms of the sequence.
$$a_{n}=\frac{(-1)^{n} x^{2 n+1}}{2 n+1}$$

AG
Ankit Gupta
Numerade Educator
00:41

Problem 136

Write the first five terms of the sequence.
$$a_{n}=\frac{(-1)^{n} x^{n+1}}{n+1}$$

AG
Ankit Gupta
Numerade Educator
01:14

Problem 137

Write the first five terms of the sequence.
$$a_{n}=\frac{(-1)^{n} x^{2 n}}{(2 n) !}$$

AG
Ankit Gupta
Numerade Educator
01:23

Problem 138

Write the first five terms of the sequence.
$$a_{n}=\frac{(-1)^{n} x^{2 n+1}}{(2 n+1) !}$$

AG
Ankit Gupta
Numerade Educator
00:41

Problem 139

Write the first five terms of the sequence.
$$a_{n}=\frac{(-1)^{n} x^{n}}{n !}$$

AG
Ankit Gupta
Numerade Educator
00:52

Problem 140

Write the first five terms of the sequence.
$$a_{n}=\frac{(-1)^{n} x^{n+1}}{(n+1) !}$$

AG
Ankit Gupta
Numerade Educator
01:13

Problem 141

Write the first five terms of the sequence.
$$a_{n}=\frac{(-1)^{n+1}(x+1)^{n}}{n !}$$

AG
Ankit Gupta
Numerade Educator
01:04

Problem 142

Write the first five terms of the sequence.
$$a_{n}=\frac{(-1)^{n}(x-1)^{n}}{(n+1) !}$$

AG
Ankit Gupta
Numerade Educator
01:21

Problem 143

Write the first five terms of the sequence. Then find an expression for the $n$ th partial sum.
$$a_{n}=\frac{1}{2 n}-\frac{1}{2 n+2}$$

AG
Ankit Gupta
Numerade Educator
01:19

Problem 144

Write the first five terms of the sequence. Then find an expression for the $n$ th partial sum.
$$a_{n}=\frac{1}{n}-\frac{1}{n+1}$$

AG
Ankit Gupta
Numerade Educator
01:27

Problem 145

Write the first five terms of the sequence. Then find an expression for the $n$ th partial sum.
$$a_{n}=\frac{1}{n+1}-\frac{1}{n+2}$$

AG
Ankit Gupta
Numerade Educator
02:23

Problem 146

Write the first five terms of the sequence. Then find an expression for the $n$ th partial sum.
$$a_{n}=\frac{1}{n}-\frac{1}{n+2}$$

AG
Ankit Gupta
Numerade Educator
00:15

Problem 147

Does every finite series whose terms are integers have a finite sum? Explain.

AG
Ankit Gupta
Numerade Educator
00:35

Problem 148

The graph represents the first six terms of a sequence.
(a) Write the first six terms of the sequence.
(b) Write an expression for the apparent $n$ th term $a_{n}$ of the sequence.
(c) Use sigma notation to represent the partial sum of the first 50 terms of the sequence.

AG
Ankit Gupta
Numerade Educator
01:46

Problem 149

Find, if possible, (a) $A-B,$ (b) $2 B-3 A,$ (c) $A B,$ and (d) $B A.$
$$A=\left[\begin{array}{l}6 \\3\end{array}\right], B=\left[\begin{array}{r}4 \\-3\end{array}\right]$$

AG
Ankit Gupta
Numerade Educator
01:30

Problem 150

Find, if possible, (a) $A-B,$ (b) $2 B-3 A,$ (c) $A B,$ and (d) $B A.$
$$A=\left[\begin{array}{cc}10 & 7 \\-4 & 6\end{array}\right], B=\left[\begin{array}{cc}0 & -12 \\8 & 11\end{array}\right]$$

AG
Ankit Gupta
Numerade Educator
01:48

Problem 151

Find, if possible, (a) $A-B,$ (b) $2 B-3 A,$ (c) $A B,$ and (d) $B A.$
$$A=\left[\begin{array}{rrr}-2 & -3 & 6 \\4 & 5 & 7 \\1 & 7 & 4\end{array}\right], B=\left[\begin{array}{lll}1 & 4 & 2 \\0 & 1 & 6 \\0 & 3 & 1\end{array}\right]$$

AG
Ankit Gupta
Numerade Educator
01:28

Problem 152

Find, if possible, (a) $A-B,$ (b) $2 B-3 A,$ (c) $A B,$ and (d) $B A.$
$$A=\left[\begin{array}{rr}-1 & 4 \\5 & 1 \\0 & -1\end{array}\right], B=\left[\begin{array}{lll}0 & 4 & 0 \\3 & 1 & -2
\end{array}\right]$$

AG
Ankit Gupta
Numerade Educator