use basic trigonometric identities to simplify the expression: sin^3 (x) + cos^2 (x) sin (x)

Use Basic Trigonometric Identities To Simplify The Expression: Sin^3 (x) + Cos^2 (x) Sin (x)

Answers

Answer 1

Given the following trigonometric expression:

[tex]sin^3x+cos^2x*sinx=?[/tex]

We will simplify the expression as follows:

First, taking sin (x) as a common

[tex]=sin\text{ }x*(sin^2x+cos^2x)[/tex]

Second, we will use the following trigonometric identity:

[tex]sin^2x+cos^2x=1\rightarrow(1)[/tex]

Finally, substitute the trigonometric identity number (1) into the given expression

[tex]=sin\text{ }x*1=sin\text{ }x[/tex]

So, the answer will be sin (x)


Related Questions

Find g(x), where g(x) is the reflection across the y-axis of f(x) = -9x - 4.
Write your answer in the form mx + b, where m and b are integers.
g(x) =

Answers

Answer: [tex]9x-4[/tex]

Step-by-step explanation:

Reflecting across the y-axis means [tex]f(x) \longrightarrow f(-x)[/tex].

[tex]g(x)=-9(-x)-4=9x-4[/tex]

Dalia's living room is 12 feet long and 10 feet wide. Her dining room
is also 10 feet wide. Write two equivalent expressions that each
represent the combined area of the two rooms.
10ft
12 ft-
Living
Room
xft-
Dining
Room

Answers

(120 + 10x) sq. feet or 10(12+x) sq. feet will be the combined area of the two rooms.

the given dimensions of the living room are given as follows,

length =12

width/breadth =10

thus the area of the living room will be,

length x breadth, i.e.

=12 x 10

=120 sq. feet

the given dimensions of the dining room are given as follows,

length= x

width/breadth=10

thus the area of the dining room can be calculated as

length x breadth

=10x sq. feet

Now, to calculate the combined area of both the rooms, we have to add the area of the dining room and the area of the living room,

that is,

(120 + 10x) sq. feet

What is area?

The area is the entire amount of space occupied by a flat (2-D) surface or an object's shape.

to learn more about area visit:

https://brainly.com/question/25292087

#SPJ9

The elephants at the zoo eat 3 1/6 buckets of bananas each day. The zookeeper bought 6 1/3 buckets of bananas. How many days will the bananas last?

Write your answer as a fraction or as a whole or mixed number.

Answers

The bananas will last 2 days at the zoo (found by division).

According to the question,

We have the following information:

The elephants at the zoo eat [tex]3\frac{1}{6}[/tex] buckets of bananas each day. The zookeeper bought [tex]6\frac{1}{3}[/tex] buckets of bananas.

Now, first we will find the number of days taken in eating 1 bucket of bananas.

[tex]3\frac{1}{6}[/tex] buckets = 1 day

Now, we will convert this mixed fraction into simple fraction.

19/6 buckets = 1 day

1 bucket = 1/(19/6) days

1 bucket = 6/19 days

Now, we have the total number of buckets as [tex]6\frac{1}{3}[/tex].

Now, after converting this mixed fraction, we have:

19/3 buckets

1 bucket =  6/19 days

19/3 buckets = (6/19)*(19/3)

19/3 buckets = 2 days

2 is a whole number.

Hence, the given buckets of bananas will last 2 days.

To know more about division here

https://brainly.com/question/18089147

#SPJ1

Solve the following linear equation using equivalent equations to isolate the variable. Express your answer as an integer, as a simplified fraction, or as a decimal number rounded to two places.

Answers

ANSWER

[tex]u=\frac{1}{5}[/tex]

EXPLANATION

We want to solve the given linear equation:

[tex]-6u=\frac{-6}{5}[/tex]

To do this, divide both sides of the equation by -6 to isolate u and simplify:

[tex]\begin{gathered} \frac{-6u}{-6}=\frac{-6}{5}\cdot\frac{1}{-6} \\ \Rightarrow u=\frac{1}{5} \end{gathered}[/tex]

That is the solution to the linear equation.

a line contains the point ( -3, -1 ) and has a slope of 1/3. which equation represents this line?

Answers

Given:

Slope = 1/3

Contain the point = ( -3,-1 )

Find-:

The equation of a line.

Explanation-:

The general equation of a line is:

[tex]y=mx+c[/tex]

Where,

[tex]\begin{gathered} m=\text{ Slope} \\ \\ c=\text{ y-intercept} \end{gathered}[/tex]

Given the slope is 1/3, then the equation of the line become.

[tex]\begin{gathered} m=\frac{1}{3} \\ \\ y=mx+c \\ \\ y=\frac{1}{3}x+c \end{gathered}[/tex]

The value of y-intercept is:

The point (-3,-1) contains the line so its satisfied the equation.

[tex]\begin{gathered} (x,y)=(-3,-1) \\ \\ \end{gathered}[/tex]

[tex]\begin{gathered} y=\frac{1}{3}x+c \\ \\ -1=\frac{1}{3}(-3)+c \\ \\ -1=-1+c \\ \\ c=-1+1 \\ \\ c=0 \end{gathered}[/tex]

So equation of line become:

[tex]\begin{gathered} y=mx+c \\ \\ y=\frac{1}{3}x+0 \\ \\ y=\frac{1}{3}x \\ \\ 3y=x \\ \\ x-3y=0 \end{gathered}[/tex]

The final equation of line is:

[tex]x-3y=0[/tex]

Which of the following is the correct mathematical expression for:
The difference between three times a number and 4

Answers

Answer:

3x - 4

Step-by-step explanation:

"Difference" is a clue word that tells you to use subtraction. The other clue word is "times" but that means times, or multiplication and is pretty straight forward.

"Three times a number" means to multiply a number, but we don't know the number, so we use a variable (a letter). I put x but you could use n or c or almost any letter for the variable.

"the difference of ___ and ___" means to subtract those two things.

So we get 3x - 4

Put the following equation of a line into slope-intercept form, simplifying all fractions.
4x-20y=-160

Answers

The equation of the line 4x-20y = -160 in the slope intercept form is y = x/5 + 8 .

The equation of the line in slope intercept form is written as

y = mx + c ,

where m is the slope of the line , and c is the y intercept .

In the question ,

the equation of the line is given

equation of line is given as 4x-20y = -160

to convert the equation in slope intercept form , we rewrite it as

20y = 4x+160

dividing both sides by 20 ,

we get

20y/20 = 4x/20 + 160/20

y = x/5 + 8

hence ,the slope intercept form is y = x/5 + 8 , where 8 is the y intercept and 1/5 is the slope .

Therefore , the equation of the line 4x-20y = -160 in the slope intercept form is y = x/5 + 8 .

Learn more about Lines here

https://brainly.com/question/21206550

#SPJ1

The table shows the number of restaurants in five different cities Cities numbers of restaurants Carlsbad 489 potters vale 261 little hath 282 edgbaston 216 barrow 317 how many more restaurants are there in Carlsbad than in barrow?

Answers

To answer this question, we will use the next table (obtained from the Question Tab):

City -------- Number of restaurants

Carlsbad 489

Potter Valley 261

Little Heath 282

Edgbaston 216

Barrow 317

If we want to know how many more restaurants there are in Carlsbad than in Barrow, we need to subtract the number of restaurants in Barrow from Carlsbad as follows:

[tex]489-317=172[/tex]

From the table, we have that in Carlsbad there are 489 restaurants, while there are 317 in Barrow.

We can check this as follows:

In summary, we can say that there are 172 more restaurants in Carlsbad than in Barrow.

El área de un sector circular de un círculo con radio igual a 8cm y ángulo central igual a 56° es aproximadamente

Answers

The sectorial area of the circle is equal 31.3cm^2

Area of a Sector

The formula for the b of the sector of a circle is /360o (r2) where r is the radius of the circle and  is the angle of the sector.

Area of a Sector of Circle = (θ/360º) × πr^2, where, θ is the sector angle subtended by the arc at the center, in degrees, and 'r' is the radius of the circle.

Data;

Radius - 8cmangle = 56 degrees

The area of the sector can be calculated using the formula given

[tex]A = \frac{\theta }{360} * \pi r^2[/tex]

Substituting the values into the formula;

[tex]A = \frac{\theta }{360} * \pi r^2\\A = \frac{56}{360}* \pi * 8^2\\A = 31.27cm\\A = 31.3cm^2[/tex]

The area is equal 31.3cm^2

Translation:

The area of a circular sector of a circle with radius equal to 8cm and central angle equal to 56 degrees.

Learn more on area of a sector here;

https://brainly.com/question/22761976

#SPJ1

please help meeee i am lost

Answers

Answer:
The sum of a sequence is known as a series. Thus means a harmonic series is infinite with no limit

Find the vertex of the parabola y=2x^2+8x+7.

Answers

Hi i hope this helps you out

How many zeroes are in the product of 40 x 107? O A. 6 B. 7 O C. 8 O D. 9

Answers

We need to count the number of zeros in a number multiplied by a power of 10. Which is shown below:

[tex]40\cdot10^7[/tex]

The power of 10 will add a certain number of zeros, which is equal to the expoent of the power, in this case it's 7, but there is one more zero which is present in the "40", therefore the total number of zeros will be 8.

Use fundamental identities to find the value. Step by step can u explain.

Answers

To answer this question, we will use the following diagram as reference:

To determine the tangent of θ, we have to find the value of x.

To find x, we use the Pythagorean theorem and get:

[tex]4^2=3^2+x^2.[/tex]

Therefore:

[tex]x=\sqrt{4^2-3^2}=\sqrt[]{7}.[/tex]

Therefore:

[tex]\tan \theta=\frac{3}{\sqrt[]{7}}.[/tex]

Answer:

[tex]\tan \theta=\frac{3}{\sqrt[]{7}}.[/tex]

help meeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

Answers

[tex]P(0)=0.023(0)^3-0.289(0)^2+3.068(0)+55.170=55.17[/tex]

Miss sheet,owner of the Bedspread shop knows his customers will pay no more than $145 for a comforter Misu wants a 40percent markup on selling price what is most that Misu can pay for a comforter?

Answers

The price that Misu can pay for a comforter based on the markup percentage is $103.57.

How to calculate the value?

From the information, the Bedspread shop knows his customers will pay no more than $145 for a comforter Misu wants a 40 percent markup on selling price.

Let the selling price be represented as x. Based on the information given, this will be illustrated as:

x + (40% × x) = 145

x + 0.4x = 145

1.4x = 145

Divide

x = 145/1.4.

x = 103.57

The selling price will be $103.57.

Learn more about percentages on:

brainly.com/question/24877689

#SPJ1

6. Suppose the class takes a test and the following averages are obtained: mean = 80, median= 90, and mode = 70. Tom, who scored 80, would like to know if he did better than half the class. What is your response?

Answers

We know that the mean is 80, the median is 90, and the mode is 70. This means that the majority of students got an 80 on the test.

However, the median is 90, which means half of the class is below 90 where Tom's grade is placed.

Hence, he did not do better than half of the class.

Can I please get answer for a and b. I just need the answers. Thanks

Answers

When we have a function and want to evalueate it for some "x", we just substitute every "x" with the value in parenthesis. So, to evaluate f(a + 2), we have x = a + 2, so we need to substitute every "x" in the function with a + 2:

[tex]f(a+2)=(a+2)^2-2(a+2)+1[/tex]

Now, to simplify, we first need to use the distributive property on the second parenthesis and evaluate the binomial in the first:

[tex]f(a+2)=a^2+4a+4-2a-4+1[/tex]

Now, we group the like-terms and add them:

[tex]\begin{gathered} f(a+2)=a^2+4a-2a+4+4+1 \\ f(a+2)=a^2+2a+1 \end{gathered}[/tex]

For yhe other one, Let's do each term and then make the substraction:

[tex]\begin{gathered} f(a+h)=(a+h)^2-2(a+h)+1 \\ f(a+h)=a^2+2ah+h^2-2a-2h+1 \\ f(a+h)=a^2+h^2+2ah-2a-2h+1 \end{gathered}[/tex][tex]f(a)=a^2-2a+1[/tex]

So:

[tex]\begin{gathered} f(a+h)-f(a)=a^2+h^2+2ah-2a-2h+1-(a^2-2a+1) \\ f(a+h)-f(a)=a^2-a^2+h^2+2ah-2a+2a-2h+1-1 \\ f(a+h)-f(a)=h^2+2ah-2h \end{gathered}[/tex]

cost equationcost of producing 7 unitswhat is the break point

Answers

Answer:

Part A: C(x) = 0.068x+0.8

Part B: 1.28

Part C: 9.76

Explanation:

Part A:

The cost C equals

cost = revenue - profit

[tex]C(x)=R(x)-P(x)[/tex]

which is

[tex]C(x)=0.15x-(0.082x-0.8)[/tex][tex]C(x)=0.15x-0.082x+0.8[/tex][tex]\boxed{C\mleft(x\mright)=0.068x+0.8}[/tex]

Part B:

The cost of producing 7 units is found by putting in x = 7 into the above equation. This gives

[tex]C(7)=0.068(7)+0.8[/tex][tex]C(7)=1.28[/tex]

Hence, the cost of producing 7 items is 1,28 million dollars.

Part C:

To break even, the cost must equal the revenue

[tex]R(x)=C(x)[/tex]

or

[tex]0.15x=0.068x+0.8[/tex]

subtracting 0.068 from both sides gives

[tex]0.082x=0.8[/tex]

dividing both sides by 0.082 gives

[tex]\boxed{x=9.76}[/tex]

which is the break-even point

the sum of two consecutive natural number is 36 find the number​

Answers

The correct answer is 18 because we need to divide 36 by 2 and it comes 18.
So, simply if we add 18 to itself comes 36.

What is an equation of the line that passes through the point (8,0)(8,0) and is parallel to the line x-4y=20x−4y=20?

Answers

The equation of the line that passes through the point (8, 0) is parallel to the line x - 4y = 20 is 1/4x - y = 2

Given,

The equation of the line: x - 4y = 20

The points which the line passes through, (x₁, y₁) = (8, 0)

We have to find the equation of the line parallel to the given line.

The formula for the slope intercept form:

(y - y₁) = m(x - x₁)

m is the slope of the line.

Lets find the slope of the line given.

x - 4y = 20

x = 20 + 4y

x - 20 = 4y

y = (x - 20) / 4

y = 1/4x - 5

Here, slope of the line is 1/4

Now, substitute the slope of the line and (x₁, y₁) in the slope intercept formula to get the equation of line parallel to the given line

(y - y₁) = m(x - x₁)

(y - 0) = 1/4(x - 8)

y = 1/4x - 8/4

y = 1/4x - 2

1/4x - y = 2

Therefore,

The equation of the line that passes through the point (8, 0) is parallel to the line x - 4y = 20 is 1/4x - y = 2

Learn more about equation of the line here:

https://brainly.com/question/19699006

#SPJ1

72.7% to nearest 10th percent

Answers

Answer:

72.7% to nearest 10th percent would be 73%!

Step-by-step explanation:

Hope it helps! =D

Sjsjsjshsxjxhxhxhxhzh27272727

PLEASE HURRY
What is the value of the expression 45x − 16 if x is equal to −6?

Answers

Answer:

-286

Step-by-step explanation:

45(-6)-16

= -270 - 16

= -286

Step-by-step explanation:

45x - 16

x = -6

45(-6) - 16

-270 - 16

-286

Hope this helps! :)


Select the correct answer.
What is the product of (7) (-16)(-7) (-1)?
A.
B.
-7
9
B. -16
C. -
D. 192

Answers

The product of  (7) (-16)(-7) (-1) is - 784 by using simple multiplication.

What is multiplication?

Finding the product of two or more numbers in mathematics is done by multiplying the numbers. It is one of the fundamental operations in mathematics that we perform on a daily basis. The symbols for multiplication are a cross (x), an asterisk (*), and dot (.). You seem to utilize the cross a lot when you write in your notebooks. In both algebra and computer languages, the asterisk and dot are symbols (higher mathematics).

7 × -16 = -112

-112 × -7 = 784

784 × -1 = -784

To know more about multiplication click here:

https://brainly.com/question/26583342

#SPJ13

2. Math on the Spot Solve each equation.
A. 3n+ 1 = 19
B. 21 = -2p - 5

Answers

A.

[tex]3n =19 - 1 \\ 3n = 18 \\ \frac{3n}{3} = \frac{18}{3} \\ n = 6[/tex]

B.

[tex]21 + 5 = - 2p \\ 2p = - 26 \\ \frac{2p}{2} = \frac{26}{2} \\ p = 13[/tex]

HOPE THIS HELPS.

Point DD is located at (-6,-5)(−6,−5) on the coordinate plane. Point DD is reflected over the xx-axis to create point D'D ′ . What ordered pair describes the location of D'?D ′ ?

Answers

The ordered pair that describes the location of N is (2,6)

Given:

N's coordinates are: (-2,-6)

Point N ′ is produced by reflecting point N over the y-axis.

By reflecting point N' over the x-axis, the final point N" is produced.

x , y = -x , y

N(-2 -6) = N'(2 6)

To locate the ordered pair describing where N" is located.

Point N's coordinates are (-2,-6). Point N ′ is produced by reflecting point N over the y-axis.

x , y = -x , y

N(-2 -6) = N'(2 6)

The resultant point N" is created by reflecting point N' over the x-axis.

The ordered pair for point N" is therefore (2,6) gives its location.

Learn more about ordered pairs at

https://brainly.com/question/22312665

#SPJ9

What is the correct formula for the volume of a cone? Is the correct answer option A B or C?

Answers

The formula for the volume of a cone is a third of the product of pi, its height h and the square of its radius r. Then, it is:

[tex]\frac{1}{3}\pi r^2h[/tex]

Answer: C

help meeeeeeeeeeeeeeeeeeeeeeee pleaseeeeee

Answers

Answer:

it would be 600

I need help on these questions

Answers

Question 16

[tex](f(x), g(x))=x^2, (x-9)[/tex]

Note it wants the pair, so you just include the definitions of the functions, not f(x)= and g(x)=

Question 17

[tex](f(x), g(x))=\sqrt{x}, 9+\sqrt{x}[/tex]

The values for first question are f(x) = x², g(x) = (x - 9) and for second question f(x) = √x, g(x) = 9 + √x.

A function may be defined as an expression in which for one value of input variable x there is only one value of output variable y. The input variable is called independent variable and output variable is called dependent variable. A composite function is the one which is written as a combination of two function. For two given functions f(x) and g(x) the composite functions are f(g(x)) and g(f(x)). In the first question the composite function is F(x) = (x - 9)². the parent functions will be f(x) = x² and g(x) = (x - 9).

in the second question the composite function is H(x) = √(9 + √x). The parent functions will be f(x) = √x and g(x) = 9 + √x.

Learn more about Composite functions at:

brainly.com/question/17749205

#SPJ1

3.Justify each step of the solution by stating the name of the property that was used to get to each step.Given: Step 1: 1.________________________________Step 2: 2. _______________________________Step 3: 17x = 403. _______________________________Step 4: 4. _______________________________Answer:

Answers

We are given the following equation:

[tex]2(10-13x)+9x=-34x+60[/tex]

In the first step we will use the distributive property on the left side:

[tex]20-26x+9x=-34x+60[/tex]

In step 2, we will add like terms on the left side using associative properties of addition and subtraction and we will subtract 20 from both sides, we get:

[tex](20-20)+(-26x+9x)=-34x+(60-20)[/tex]

Solving the operations we get:

[tex]-17x=-34x+40[/tex]

In step 3 we will add 34x to both sides, this is the inverse additive inverse:

[tex](-17x+34x)=(-34x+34x)+40[/tex]

Solving the operations:

[tex]17x=40[/tex]

In step 4, we divide both sides by 17, this is the division property of equality:

[tex](\frac{17x}{17})=\frac{40}{17}[/tex]

Solving the operations:

[tex]x=\frac{40}{17}[/tex]

Construct a triangle with the given measures. Label all sides and angle measurements. 1. 4 cm, 6cm

Answers

Answer: angle = 33.7° ; angle =56.3 ° ;side AC = 7.2cm.

Given the two sides measurement,

• Assuming that the other side represent x and the other side represent y,( 4cm;6cm) , and that we are drawing a right angle triangle .We can constuct a triangle as follows :

• We can find the value of side h by using Pythagorean theorem:

[tex]\begin{gathered} \text{ h = }\sqrt[]{x^2+y^2}\text{ } \\ \text{where x = 4}cm\text{ and y = 6}cm\text{ , } \\ \therefore\text{ h = }\sqrt[]{4^2+6^2} \\ \text{ = 7.2 }cm \end{gathered}[/tex]

• Subsequently, we will find angle angle , as shown in the diagram above as follows:

[tex]\begin{gathered} \text{For angle }\beta \\ Tan\text{ }\beta\text{ = opposite /adjacent } \\ \text{Tan }\beta\text{ = }\frac{AB}{BC\text{ }} \\ Tan\text{ }\beta\text{ = }\frac{6}{4} \\ \beta\text{ = }\tan ^{-1}(\frac{6}{4}) \\ \text{ =56.3}\degree \end{gathered}[/tex]

• Since we have angle ,= 56.3 °, ,we can find, angle :

,

• + + 90° = 180 °,....(angles in a triangle adds up to 180°)

∴ = 180° -90° -56.3°

=33.7°

Other Questions
Find the slope of the line given its graph. A sample of people who recently hired an attorney yielded the following information about their attorneys.Number of PeopleWould You Recommend Your Attorney to a Friend?YesNoNot sureThree people who provided information for the table were selected at random. Determine the probability that the first two would not recommend their attorney and the third is not sure if he or she would recommend their attorney. Ralph Kansky was hired as an administrative assistant for Hereford Cattle Company. His annual salary is $98,280. What is his weekly salary? Which of the following equations shows how substitution can be used to solve the following system of equations? A technician examines different electrical devices to determine the one that is the most energy efficient. While conducting a test, he notes that one of these devices consumes 550 000 J of energy and loses 315 000 J at the same time. What is the energy efficiency of this device? Question 5:Write an equivalent expression for (15)4 Question 16 of 22What is the product of (2x+3x - 1) and (3x+5)?A. 6x3 +19x2 +12x-5B. 6x3 + 10x2 +15x-5C. 6x3 +9x? - 3x-5D. 6x3 +19x2 - 12x+5 (02.01 LC)When reading an informational text, how do you identify the author's thesis statement?A: The thesis statement is the first sentence of the introduction, in which the author introduces the topic for the first time.B: The thesis statement is found at the end of the conclusion and summarizes the supporting details in the text.C: The thesis statement is the sentence found at the beginning of each body paragraph and is followed by supporting details. D: The thesis statement is the sentence in the introduction that states the author's specific ideas about the topic. If a 25% price increase for product a causes a 10% decrease in its quantity demanded, but no change in the quantity demanded for product b, what is the cross-price elasticity of these goods? round your answer to one decimal place. Solve the literal equation to isolate V2 P1V1=P2V2 A satellite orbiting Earth at an orbital radius r has a velocity v. Which represents the velocity if the satellite is moved to an orbital radius of 5r?(1 point) A recipe of chicken marinade says mix 3 parts with oil with 2 parts soy sauce and 1 part orange juice if you need 42 cups of marinade in all how much of each ingredient should you use 4 times 10 by the power8 subtract 9times 10 by the 7 Frances Trollope was a respected author in England, who after returning from living in the U.S. for three years, wrote the travelogue book Domestic Manners of the Americans, 1832. How does she describe her experience at a revivalist camp meeting? After reading the chapter, select a sentence or brief paragraph to highlight why you would or would not want to attend such a meeting during this time period. Include your textual exvidence in your journal response. sal's orange stand made that show a relationship between the total number of oranges and the number of boxes they sell. Each box has the same number of oranges. Sal made an error in one of the boxes. The 7th graders at Wilson Middle School are taking a field trip to the science museum. So far, 12 students have turned in a total of $81 to pay for their ticket.What is the constant of proportionality equation for this problem?If all 72 students turn in their ticket money, how much money would be collected?Group of answer choicesy = 1/12(x) $6.75 would be collectedy = 12(x) $840.00 would be collectedy = 6.75(x) $486.00 would be collectedy = 81(x) $5832.00 would be collected Why role do muscles play in helping bones A neurologist is studying an older patient who is suffering from dementia and Alzheimer's and is experiencing difficulties with long-term memory. In this image, which part of the brain might the doctor especially study for damage?A human brain with the major parts identified by numbers.Question 7 options:1348 (11^9) over (15^6) to the 4th powerA 11^6 + 4/15^6 +4B 11^36/15^24C 11^9x4/15^6x4D 11/13/15^10 How do you know the writer used a point-by-point comparison strategy in the passage?a.The writer combines information about both kinds of books in each paragraph.b.The writer discusses e-books for several paragraphs and then discusses print books until the end.c.The writer covers all the information about e-books and then print books.d.The writer moves between the two kinds of books, back and forth, throughout the passage.