each side of a square is increasing at a rate of 8 cm/s. at what rate (in cm2/s) is the area of the square increasing when the area of the square is 16 cm2? incorrect: your answer is incorrect. cm2/s

Answers

Answer 1

The rate of the square increasing when the area is 16 cm² is 64 cm²/s. The result is obtained by using basic derivative rules.

How to count the rate of a square increasing?

The rate of a square increasing can be counted by the derivative of the area of the square as a function of time.

dA/dt = 2s ds/dt

Where s is side length.

If each side of a square is increasing at a rate of 8 cm/s, what is the rate of the square increasing when the area is 16 cm²?

We have the side of the square as the function of time.

ds/dt = 8 cm/s

When the area is 16 cm², the side length is

A = s²

16 = s²

s = √16

s = 4 cm

The rate of the square increasing is

dA/dt = 2s ds/dt

dA/dt = 2 × 4 × 8

dA/dt = 64 cm²/s

Hence, the rate of the square increasing when the area is 16 cm² is 64 cm²/s.

Learn more about rate of a square increasing here:

brainly.com/question/10659111

#SPJ4


Related Questions

a construction worker is pouring concrete stairs. the first step requires 1.8 cubic feet of concrete, and the first 5 steps require a total of 27 cubic feet. if the steps follow an arithmetic series, how much concrete is required for the first 12 steps?

Answers

If the steps follow an arithmetic series, the concrete required for the first 12 steps is 140.4.

Given, the first term of the arithmetic series, a=1.8 and the sum of first five terms that is s5=27, we have to find the sum of first 12 steps.

The formula to calculate the sum of the terms in AP is

Sn = n/2 {2a + (n - 1) d}

S5=5/2(2(1.8) +(5-1)d)

27=2.5(3.6+ 4d)

27=9+10d

27-9=10d

18=10d

d=18/10

d=1.8

The common difference d is 1.8.

Now we have to find S12,

S12=12/2(2(1.8) +(12-1)1.8)

= 6(3.6+19.8)

=6(23.4)

=140.4

S12=140.4

Therefore, the concrete required for the first 12 steps is 140.4.

To learn more on arithmetic series here:

https://brainly.com/question/16415816#

#SPJ4

The scale of a map is 1.5 centimeters =
120 kilometers. If two cities are
4.75 centimeters apart on the map,
what is their actual distance?
A. 420 km
B. 390 km
C.
380 km
D. 360 km

Answers

If 1.5cm : 120km
1cm : 80km
4.75cm : 380km

Hence the answer is c which is 380 km

What is the slope of the line passing through the following two points.
P1 (4,6) and P2 (5, 9)

Enter your answer in the box.

Answers

you need to plug the coordinates into the slope formula, which is m=(y2-y1)/(x2-x1).

m=(9-6)/(5-4)

m=(3)/(1)

m=3

What is the answer to this question

Answers

Answer:

x = 11

Step-by-step explanation:

Let's have  one of the numbers be represented by the variable, x,  and the other number be represented with the variable, y

Since the sum of the two numbers is 55, we can write the following equation:

x + y = 55

Then since one number is 4 times as large as the other, we can write:  y = 4x

We can now substitute this expression for y into the second equation and solve by

combining like terms and using inverse operations to solve for x:

x + y = 55

x + 4x  = 55

5x = 55

5x/5 = 55/5

x = 11

One of the numbers is 11.

Since the sum of the numbers is 55, the other number will be 44.

Answer:

11 and 44

Step-by-step explanation:

→ Write 2 equations

x + y = 55

y = 4x

→ Substitute bottom equation into top

x + 4x = 55

→ Solve

x = 11

→ Find y

4 × 11 = 44

A ladder 13m long reaches a window which is 5m above the ground , on one side of the
street. Keeping its foot at the same point,
the ladder is turned to the other side of the street
to reach a window at a height of 12m. Find the
width of the street.

Answers

The ladder is 13 m long and leans against a window 5 m high, then the ladder leaned to the other side without moving its feet to reach the 12 m high window.

How to find the width of the street?

if we imagine a leaning ladder it will look like a right triangle and it will remind us of the Pythagorean theorem. do you remember the pythagorean theorem?

The Pythagorean theorem explains the relationship or relationship between the lengths of the sides of a right triangle.

The Pythagorean theorem reads: "The square of the length of the hypotenuse (hypotenuse) in a right triangle is equal to the sum of the squares of the lengths of the other sides".

in the picture, let's say if the width of the street is a, the height of the window is b and the length of the stairs is c.

in this case we will find the width of the street, namely a, then we use formula a² = c² - b² .

then it will be

b = 12

c = 13

a² = c² - b²

a² = 13² - 12²

a² = 169 - 144

a² = 25

a = 5

So the width of the street is 5 m

4^5-9x = 1/8^x-2

what is x equals? and the steps
.. please

Answers

You can ask where you don't understand.

A cheetah can run 18.75 miles in 1/4 hours. What is its speed in miles per hour?

Answers

Answer: miles per hour = mi/hr = 17.5mi/0.25hr = 17.5*4mi/0.25*4hr = 70mi/hr

Step-by-step explanation:miles per hour = mi/hr = 17.5mi/0.25hr = 17.5*4mi/0.25*4hr = 70mi/hr

Step-by-step explanation:

18.75 miles in 1/4 hour.

that is the ratio 18.75 / 1/4

but we want the miles in an hour.

so, how many 1/4 are in a whole ?

well, 4.

so we need to multiply the ratio by 4/4 (so that on one hand we multiply the denominator by 4 to make it a whole, and on the other hand we are not changing the value of the ratio) :

18.75 × 4 / (1/4 × 4) = 75 miles / 1 hour = 75 mph.

An artist creates a cone shaped sculpture for an art exhibit. If the sculpture is 15 feet tall and has total volume 235.5 cubic feet, what is the radius of the sculpture? Use 3.14 for pi

Answers

Answer: r = 19.35 ft

Step-by-step explanation:

[tex]Volume = V = \pi r^{2} \frac{h}{3} \\235.5 = \pi r^{2} 15/3\\r^{2} = \frac{235.5}{\pi} 5\\r = \sqrt{374.8} = 19.35[/tex]

The two-way frequency table contains data about how students access courses.


Traditional Online Row totals
Computer 28 62 90
Mobile device 46 64 110
Column totals 74 126 200


What is the joint relative frequency of students who use a computer in a traditional class?
45%
37%
28%
14%

Answers

The joint relative frequency of students who use a computer in a traditional class is of:

37%.

How to obtain a relative frequency?

The relative frequency of an event in an experiment is calculated as the number of desired outcomes in the context of the experiment divided by the number of total outcomes in the context of the experiment.

In this problem, we want the joint relative frequency of students who use a computer in a traditional class, hence the total and desired outcomes are given as follows:

Total outcomes: 74 students in a traditional class.Desired outcomes: 28 students using a computer in a traditional class.

Hence the joint relative frequency of students who use a computer in a traditional class is calculated as follows:

28/74 = 37%. (rounded down).

More can be learned about relative frequencies at https://brainly.com/question/1809498

#SPJ1

Answer:

14%



Step-by-step explanation:

1. I took the test

2.Likes running and swimming=28

Total=200

28/200=.14

.14 in percent form is 14%


PLS GIVE BRAINLIST MEAN THE WORLD

Determine the effective tax rate for a taxable income of $63,425. Round the final answer to the nearest hundredth.

Answers

Answer:

The effective tax rate for a taxable income of $63,425 is 15.18%.

Step-by-step explanation:

There are 10 squares and 2 circles. What is the simplest ratio of circles to squares?

Answers

Answer: 5:1

Step-by-step explanation: 10:2 can be simplified by dividing both by 2, making it 5:1

What is the solution to the following system?

Answers

The solution to the system is x = 0, y =2, z = 5

How to find the solution to the system?

Given the following system:

x+ 2y+z=9      -------- (1)

x- y+3z = 13    -------- (2)

2z = 10            -------- (3)

From (3):

2z = 10

z = 10/2 = 5

Put z = 5 into (1) and (2):

x+ 2y+z=9

x+ 2y+5 = 9

x +2y = 9-5

x +2y = 4     -------- (4)

x- y+3z = 13

x -y + 3(5) = 13

x-y + 15 = 13

x-y = 13 -15

x-y = -2     --------   (5)

Using elimination method on (4) and (5):

Subtracting (5) from (4):

x +2y = 4

x-y =   -2

3y = 6

y = 6/3 = 2

Put y = 2 into (4):    

x +2y = 4

x + 2(2) = 4

x + 4 = 4

x = 4-4 = 0

Therefore, the solution is x = 0, y =2, z = 5. The 3rd option is the answer.

Learn more about system of equations on:

https://brainly.com/question/13729904

#SPJ1

3[tex]3 divided by 19.5[/tex]

Answers

Answer:

1.38461538462

Step-by-step explanation:

(Please help quick!)


Which rectangle has the same area as the triangle
shown?

Answers

Bottom left. The triangle’s area is 12. The bottom left is the only one that’s equal to 12.

The rectangle with the sides 4 and 3 is the required rectangle.

The correct option is third shape.

What is area?

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

The area of the triangle,

= 1/2 x base x height

= 1/2 x 6 x 4

= 12 square millimeters.

And rectangle has the same area as the triangle.

The rectangle with the sides 4 and 3 is the required.

Therefore, the rectangle with the sides 4 and 3 is the required rectangle.

To learn more about the area;

https://brainly.com/question/27683633

#SPJ2

Neal buy a board game. He pay for the board game and pay 1.54 in ale tax. The ale tax rate i 5.5% what i the original price of the board game before tax

Answers

Answer:

$28

Step-by-step explanation:

5.5%=0.055

1.54/0.055=28

1= Prt.
You deposit $2,500 into an account
earning Simple interest. The
interest rate is 1.75%
How much money will be in the
account after 8 years?
-How much interest will be earned
5 years?
in

Answers

Part a

There will be $2850 in the account after 8 years

Part b

The amount of interest earned in 5 years is $218.75

The principal amount = $2500

The interest rate = 1.75%

The time period = 8 years

Part a

The simple interest

A = P(1  + rt)

Substitute the values in the equation

A = 2500(1 + (1.75/100)×8)

A = 2500( 1 + 0.14)

A = 2500( 1.14)

A = $2850

Part b

The time period = 5 years

Simple interest = Prt

= 2500 × (1.75/100) × 5

= 2500 × 0.0175 × 5

= $218.75

Hence,

Part a

There will be $2850 in the account after 8 years

Part b

The amount of interest earned in 5 years is $218.75

Learn more about simple interest here

brainly.com/question/25845758

#SPJ1

The first container of milk contains twice as much milk as the second contamer After John uses 2 galions of milk from the second container and 3 gallons of milk from the first container, the first container has 45 times as much milk as the second, How many gallons of milk were in each container originally?

Answers

The gallons of milk were in each container originally is 2.4 and 4.8 gallons respectively.

How to calculate the gallons?

Let us say that:

V₁ = initial gallons in the first container

V₂ = initial gallons in the second container.

From the problem statement, we can create the expression:

V₁ = 2 V₂

V₁ – 3 = 45 (V₂ – 2)

Combining the two expressions:

2 V₂ – 3 = 45 (V₂ – 2)

2 V₂ – 3 = 45 V₂ – 9

2.5 V₂ = 6

Divide

V₂ = 6 / 2.5

V₂ = 2.4 gallons

V₁ = 2 V₂:

= 2 × 2.4

= 4.8 gallons

Learn more about gallons on:

https://brainly.com/question/1106482

#SPJ1

Complete question

The first container of milk contains twice as much milk as the second contamer After John uses 2 galions of milk from the second container and 3 gallons of milk from the first container, the first container has 4.5 times as much milk as the second, How many gallons of milk were in each container originally?

Help!! I need this ASAP!

Answers

The given expression rewritten in simplified exponential form is [tex]5x^{\frac{3}{2}}[/tex]

Simplifying an expression

From the question, we are to rewrite the given expression is simplified exponential form.

The given expression is

[tex]\sqrt{\sqrt{25^{2} x^{6} } }[/tex]

First, we will evaluate the inner square root

[tex]\sqrt{25^{\frac{2}{2} } x^{\frac{6}{2} } }[/tex]

[tex]\sqrt{25 x^{3 } }[/tex]

Simplifying further

[tex]\sqrt{25 } \times \sqrt{x^{3}}[/tex]

[tex]5\times x^{\frac{3}{2}}[/tex]

= [tex]5x^{\frac{3}{2}}[/tex]

Hence, the expression in simplified form is [tex]5 x^{\frac{3}{2}}[/tex]

Learn more on Simplifying an expression here: https://brainly.com/question/21862471

#SPJ1

HELP WHATS IS A multi step equation that has a variable on both side that equals 10

Answers

Answer:

Step-by-step explanation:

an equation that takes two or more steps to solve is called a multi-step equation. let's take a multi-step equation that will satisfy the given condition:

4x - 8 = 22 + x

4x -x = 22 + 8      

3x = 30

x = 10          

Two number have a product of 7. One of the number i 4 2/3, what i the other number?

Answers

Answer:

  1 1/2

Step-by-step explanation:

You want the other number when one of the two numbers that have a product of 7 is 4 2/3.

Solution

Let x represent the unknown factor. Then we have ...

  (4 2/3)x = 7

  (14/3)x = 7 . . . . . . write as improper fraction

  x = (3/14)(7) . . . . . multiply by the inverse of the coefficient of x

  x = 3/2 = 1 1/2

The other number is 1 1/2.

Find an
for a line parallel to
4x + 5y + 2 = 0, with an
an x-intercept of 3

Answers

The equation of the parallel line is 4x + 5y - 12 = 0

How to determine the line equation?

The equation is given as

4x + 5y + 2 = 0

The x-intercept is also given as

x-intercept = 3

We have

4x + 5y + 2 = 0

Make y the subject

5y = -4x - 2

Divide through by 5

y = -4x/5 - 2/5

The equation of a line can be represented as

y = mx + c

Where

slope = m

By comparing the equations, we have:

m = -4/5

This means that the slope of 4x + 5y + 2 = 0 is =4/5

The slopes of parallel lines are equal

This means that the slope of the other line is -4/5

The equation of the parallel line is then calculated as

y = m(x - x₁) +y₁

Where

m = -4/5

(x₁, y₁) = (3, 0) i.e. the x-intercept

So, we have

y = -4/5(x - 3) + 0

Multiply through by 5

5y = -4(x - 3)

Open the brackets and evaluate

5y = -4x + 12

This gives

4x + 5y - 12 = 0

Hence, the parallel line has an equation of 4x + 5y - 12 = 0

Read more about linear equations at

brainly.com/question/4074386

#SPJ1

what is the best solution to this equation 2log2x-log2(2x)=3

Answers

The best solution for the given equation is x=4

What are logarithmic functions?

The inverse function to exponentiation in mathematics is called the logarithm. Accordingly, the exponent to which b must be raised in order to obtain a number x is determined by its logarithm to the base b.

Use Property:

logb(xy)=logbx+logby and logby = x ⇔ x^b = y

log2(x(x−2))=3
2^3 =x^2 −2x
8=x^2−2x
0=x^2−2x−8
0=(x−4)(x+2)
x−4=0
or
x+2=0
x=4
or
x=−2
Hence, x=4

To know more about logarithmic function click here,
https://brainly.com/question/28144471
#SPJ1

Answer: X=16

Step-by-step explanation:

trust,, also good luck to plato 2b algebra people

a recent survey of 6 social networking sites has a mean of 9.05 million visitors for a specific month. the standard deviation was 5 million. find the 98% confidence interval of the true mean. assume the variable is normally distributed. round your answers to at least two decimal places.

Answers

The 98% confidence interval of the true mean is 43.02 million < true mean < 13.80

Given,

Number of social networking sites being surveyed = 6

Sample mean = 9.05 million visitors per month

Standard deviation = 5 million

We have to find the 98% confidence interval of the true mean;

Here,

Sample mean, x = 9.05 million

Standard deviation, σ = 5 million

Sample size, n = 6

z score of 98% is 2.326

Now,

9.05 million - 2.326 × (5 million / √6) < true mean < 9.05 million + 2.326 × (5 million / √6)

43.02 million < true mean < 13.80

Therefore,

The 98% confidence interval of the true mean is 43.02 million < true mean < 13.80

Learn more about true mean here;

https://brainly.com/question/2253744

#SPJ4

The graph of a linear function passes through (−8,−4) and (4, 5). What is the equation of the function? Please help.

Answers

Answer:  y=(3/4)x+2

Step-by-step explanation:

1. Find the slope (change of y/change of x)

(5-(-4))/(4-(-8)

9/12

SLOPE: 3/4

2. Find the y-intercept. Insert the points into an equation and find b.

5=(9/12)(4)+b

5=3+b

b=2

Y-INTERCEPT=2

Solve the equation -4(x - 1) + 6x =34 for x

Answers

Answer:

Step-by-step explanation:

-4(x - 1) + 6x =34

-4x + 4 + 6x = 34

-4x + 6x + 4 = 34

2x + 4 = 34

2x + (4-4) = (34-4)

2x = 30

2x/2 = 30/2

x = 15

Which transformation can be applied to the blue figure to create the red figure?

Answers

The sequence of transformations that we should apply is the one that appears on the top left option:

Reflection across the y-axis followed by a rotation of 90° counterclockwise.

Which sequence of transformations map the blue figure into the red one?

We can see that the blue figure is on the third quadrant, and the "spiral" part is pointing upwards.

First, we would want to apply a rotation of 90° clockwise, this will move the blue figure to the second quadrant, and now the "spiral" part will point thowards the right.

Now you can see that the red figure is a reflection along the y-axis of the blue figure, so we need to apply that transformation.

Concluding, the sequence of transformations is:

rotation of 90° clockwise.reflection across the y-axis.

Notice that this is equivalent to:

Reflection across the y-axis.rotation of 90° counterclockwise.

Then the correct option is the one in the top left corner.

Learn more about transformations

https://brainly.com/question/4289712

#SPJ1


Find the critical value t g corresponding to a 99% confidence level, given that the sample has size n = 12

Answers

The critical value is 2.65

Given,

The confidence interval = 99%

Sample size, n = 12

We have to find the critical value;-

Critical value;-

A critical value is the test statistic's value that establishes a confidence interval's upper and lower boundaries or the level of statistical significance for a given test.

Here,

The sample size n = 12,

Then, the degrees of freedom is n - 1 = 12 - 1 = 11

The critical value= t₀.₀₀₁/2 = t₀.₀₀₅

Using the t-table and selecting df =12  and  since it’s a 2 tail the corresponding t-score is 2.65

Therefore, the critical value is 2.65

Learn more about critical value here;

https://brainly.com/question/14470673

#SPJ4

Find the Area of the figure below, composed of a rectangle with a semicircle removed from it. Round to the nearest tenths place.
4
6

Answers

20, you multiply 4x6 which equals 24 and round it to 20

Please help (Algebra 1)

Answers

The average rate of change of the function is 0.2 inches per day

How to determine the average rate of change of the function?

A rate of change describes how one quantity changes in relation to another quantity. Mathematically, it is defined as the change in one divided by the change in the other quantity.

In this case, the average rate of change of the function g(n) from n=1 to n=5 will be:

Given the function, g(n) = 10(1.02)ⁿ

average rate of change  = g(5)-g(1) / n₅-n₁

g(5) = 10(1.02)⁵ = 11.0

g(1) = 10(1.02)¹ = 10.2

                     

average rate of change  = 11.0-10.2 / 5-1

                                        = 0.8/4

                                        = 0.2 inches per day

Therefore,  the average rate of change from n=1 to n=5 is 0.2 inches per day

Learn more about average rate of change on:

https://brainly.com/question/8728504

#SPJ1                        

3) a² + 3a - 10 = 0

I don’t know how to do this and I need to solve it by quadratic formula

Answers

A quadratic equation in one unknown;

[tex]ax^2+bx+c=0[/tex]

has two roots. In order to determine these roots, we need to apply certain operations. We can get information about the existence of these roots by discrimination. Below is the discrimination formula.

[tex]D=b^2-4ac[/tex]

If we apply discriminant for the above equation, we obtain the following expression;

[tex]D=(3)^2-4(1)(-10)[/tex][tex]D=9+40[/tex][tex]D=49[/tex]

If the discriminant number is greater than [tex]0[/tex], the equation has two real and distinct roots.

[tex]D > 0,[/tex]   [tex]x_{1}\neq x_{2}[/tex][tex]D=0,[/tex]   [tex]x_{1}=x_{2}[/tex][tex]D < 0,[/tex]   [tex]No[/tex] [tex]Root[/tex] [tex]in[/tex] [tex]Real[/tex] [tex]Numbers.[/tex]

Now let's remember our formula for finding the roots and solve the problem using the discriminant value.

[tex]x_{1}=\frac{-b-\sqrt{D} }{2a},[/tex]    [tex]x_{2}=\frac{-b+\sqrt{D} }{2a}.[/tex]

Therefore;

[tex]x_{1}=\frac{-3-\sqrt{49} }{2}[/tex][tex]x_{1}=-5[/tex]

Other root is;

[tex]x_{2}=\frac{-3+\sqrt{49} }{2}[/tex][tex]x_{2}=2[/tex]
Other Questions
In dna replication, the strands on the original molecule are used as blank______ for the synthesis of new dna strands. compare the outcomes (prices, outputs, profits, and economic efficiencies) of a competitive market and one in which the producers are able to act and set prices as though they were a monopoly. what would antitrust law try to accomplish? Last year, Amy deposited $1000 into an account that paid 2% interest per year and $3000 into an account that paid 7% interest per year. No withdrawals were made from the accounts.Answer the questions below. Do not do any rounding.(a) What was the total interest earned at the end of 1 year?(b) What was the percent interest for the total deposited? The density of a cube is 2.0gcm3. If the mass is 128 g, what is the length of each side of the cube? Report your answer with two significant figures. In a study of the accuracy of fast food drive-through orders, one restaurant had 40 orders that were not accurate among 318 orders observed. Use a 0.01 significance level to test theclaim that the rate of inaccurate orders is equal to 10%. Does the accuracy rate appear to be acceptable? So, we have a list called gradebook that contains a list of dictionaries, where each dictionary contains four keys: name, homework, test, and exam. Imagine you wanted to get the entire dictionary for the first student in this list. What line of code would retrieve that dictionary? A customer at the store wanted to buy a different watch that was listed at $88 but had a 15% discount. Then the customer had to pay a sales tax of 5% on the dis... How did the plantation system contribute to greater agricultural production in south carolina? question 3 options: reduced restrictions for slaves led to greater productivity on large plantations. Plantations focused on only one product, making it easier to produce large quantities. With most necessities on site, the self-sufficiency of plantations led to increased production. As the need for cotton grew, slaves were forced to work through the night, to meet demand. A scuba diver's tank contains 1.47 moles of 02 and 5.53 moles of He at the endof a dive. If the pressure of the gas mixture is 12.1 atm, what is the partialpressure of He in the tank?2.19 atm2.54 atm9.56 atm15.3 atm to what does the concept aggregation refer wih regard to the society in which the rite of passage is practiced? your friend tells you he is going to start investing and would like to earn a 10% return. he says stocks make him nervous, so he will only be investing 10% in stocks and the remaining 90% will be invested in bonds. what would you say to him? Match each item tothe sphere of Earth in which it is located.ozone layerfossilsrust (iron oxide)cyanobacteriaHydrosphereAtmosphereLithosphere How do Coca-Cola, Pepsi, Unilever, and Johnson & Johnson benefit from their various strategies with regard to plastic disposal? How do you feel about what they are doing? As more settlers of European descent settled in the plains, how did this change the way of life of the American Indians who lived in the region?A) As the settlers took more land for cultivation, more American Indians willingly chose to become farmers.B) The American Indian way of life in the plains changed due to the settlers destruction of the buffalo population.C) As the railroads developed in the west, settlers began to move into the plains to trade with the American Indians.D) The American Indians joined the settlers in building cities around the railroad stations. igby and connor are both very well off financially, but igby gets most of his income from investments that he inherited from his grandfather while connor works long hours as a corporate lawyer to earn his. in terms of social class, igby would be considered , whereas connor would be . Islam was first introduced into West Africa during the rule of what Sudanic kingdom? Ghana Mali Songhai Bantu True or False: The invention of gunpowder, moveable wooden type and mosaics are closely associated with the Tang and Song dynasties. 10 - 2(4 + 12x) pls give me an equation answer, not the solution!!! romantic operas brought about a number of new, significant compositional techniques. please select all of the correct ones below. In this lesson, you analyzed how Frederick Douglass presented an argument in "Letter from Frederick Douglass to Harriet Tubman." You noticed how he developed his claim that Tubman was one of the most influential abolitionists. Think about the additional information you learned about Tubman and the abolitionist movement in Adler's text. Based on your readings today, how does one know when they have made a difference for others or left a strong legacy? Why is it important for authors to justify claims?