The notation f:S→T denotes that f is a function, also called a map , defined on all of a set S and whose outputs lie in a set T . A function f:S→T is injective if for all x,y∈S , f(x)=f(y) implies that x=y . Alternatively: a function is injective if we can uniquely recover some input x based on an output f(x) . What functions are injective?

Answers

Answer 1

Answer:

There are many. Two examples are

[tex]f(x) = x, \\f(x) = x^3[/tex]

Step-by-step explanation:

There are many examples. The simplest is

1 -

[tex]f(x) = x[/tex]

It is trivial that

[tex]\text{if \,\,\,\,} f(x) = f(y) \,\,\,\,\,\text{then} \,\,\,\,\, x=y[/tex]

2 -

[tex]f(x) = x^3[/tex]

That function is injective as well.

[tex]\text{if \,\,\,\,} x^3 = y^3 \,\,\,\,\,\text{then} \,\,\,\,\, x=y[/tex]

An example of a function that is NOT injective is

[tex]f(x) = x^2[/tex]

Notice that

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


Related Questions

What are the roots of x in -10x^2 + 12x − 9 = 0

Answers

Answer:

No roots

Step-by-step explanation:

the discriminant Δ = 12²-4×(-10)×(-9) = -216

since ∆ is negative then the equation -10x^2 + 12x − 9 = 0 has no solution .

select the point that is a solution to the system of inequalities​

Answers

Answer: B.  (-1, 0)

This point is below both the red diagonal line and the blue parabola. We know that the set of solution points is below both due to the "less than" parts of each inequality sign.  

In contrast, a point like (2,2) is above the parabola which is why it is not a solution. It does not make the inequality [tex]y \le x^2-3x[/tex] true. So this is why we can rule choice A out.

Choice C is not a solution because (4,1) does not make [tex]y \le -x+3[/tex] true. This point is not below the red diagonal line. We can cross choice C off the list.

Choice D is similar to choice A, which is why we can rule it out as well.

A sample consists of 80 separate events that are equally likely what is the probability of each?

Answers

Answer:

1/80

Step-by-step explanation:

This problem brothers is the probability of mutually exclusive events,

Given the sample space of 80 separate events, the probability of of one event happening is

Pr(each event)= [tex]\frac{1}{80}[/tex]

help me about this integral

Answers

The gradient theorem applies here, because we can find a scalar function f for which ∇ f (or the gradient of f ) is equal to the underlying vector field:

[tex]\nabla f(x,y,z)=\langle2xy,x^2-z^2,-2yz\rangle[/tex]

We have

[tex]\dfrac{\partial f}{\partial x}=2xy\implies f(x,y,z)=x^2y+g(y,z)[/tex]

[tex]\dfrac{\partial f}{\partial y}=x^2-z^2=x^2+\dfrac{\partial g}{\partial y}\implies\dfrac{\partial g}{\partial y}=-z^2\implies g(y,z)=-yz^2+h(z)[/tex]

[tex]\dfrac{\partial f}{\partial z}=-2yz=-2yz+\dfrac{\mathrm dh}{\mathrm dz}\implies\dfrac{\mathrm dh}{\mathrm dz}=0\implies h(z)=C[/tex]

where C is an arbitrary constant.

So we found

[tex]f(x,y,z)=x^2y-yz^2+C[/tex]

and by the gradient theorem,

[tex]\displaystyle\int_{(0,0,0)}^{(1,2,3)}\nabla f\cdot\langle\mathrm dx,\mathrm dy,\mathrm dz\rangle=f(1,2,3)-f(0,0,0)=\boxed{-16}[/tex]

Drivers who are members of the teamsters Union earn an average of $17.15 per hour (U.S. News & World Report). Assume that available data indicate wages are normally distributed with a standard deviation of $2.25. 1) What is the probability that wages are between $15.00 and $20.00 per hours?

Answers

Answer:

[tex]P(15<X<20)=P(\frac{15-\mu}{\sigma}<\frac{X-\mu}{\sigma}<\frac{20-\mu}{\sigma})=P(\frac{15-17.15}{2.25}<Z<\frac{20-17.15}{2.25})=P(-0.96<z<1.27)[/tex]

And we can find the probability with this difference and using the normal standard table:

[tex]P(-0.96<z<1.27)=P(z<1.27)-P(z<-0.96)= 0.898-0.169 = 0.729[/tex]

Step-by-step explanation:

Let X the random variable that represent the wages, and for this case we know the distribution for X is given by:

[tex]X \sim N(17.15,2.25)[/tex]  

Where [tex]\mu=17.15[/tex] and [tex]\sigma=2.25[/tex]

We want to find this probability:

[tex]P(15<X<20)[/tex]

And we can use the z score formula given by:

[tex]z=\frac{x-\mu}{\sigma}[/tex]

Using this formula we have:

[tex]P(15<X<20)=P(\frac{15-\mu}{\sigma}<\frac{X-\mu}{\sigma}<\frac{20-\mu}{\sigma})=P(\frac{15-17.15}{2.25}<Z<\frac{20-17.15}{2.25})=P(-0.96<z<1.27)[/tex]

And we can find the probability with this difference and using the normal standard table:

[tex]P(-0.96<z<1.27)=P(z<1.27)-P(z<-0.96)= 0.898-0.169 = 0.729[/tex]

Na figura abaixo estão representadas cinco ruas do bairro onde moram João, Marcos, Pedro, Vitor e Samuel. A localização da casa de cada menino é identificada pela inicial de seu nome. Na esquina das ruas A e D fica a escola onde todos estudam. Sabe-se que as ruas A, B e C são paralelas e que todos os meninos vão a pé para a escola, sempre pelo caminho mais curto. Se Samuel caminha 100 m até a escola, Vitor caminha 260 m, João caminha 180 m e Marcos, 270 m, qual é a distância, em metros, que Pedro percorre de sua casa até a escola?


280m
300m
340m
460m
320m

Answers

Answer:

340 m  

Step-by-step explanation:

Assume the figure looks like the one below.

We have three parallel lines cut by two transversals.

1. Lengths of segments

(a) Segment VS

If Vitor walks 260 m,  

VS + SE = 260

VS + 100 = 260

VS = 260 - 100 = 160 m

(b) Segment MJ

If Marcos walks 270 m,  

MJ + JE = 270

VS + 180 = 270

VS = 270 - 180 = 90 m

(c) Segment PV

The segments on the transversals are proportional.

[tex]\begin{array}{rcl}\dfrac{x}{90} & = & \dfrac{160}{180} \\\\x & = & 90 \times \left (\dfrac{160}{180}\right )\\\\& = &\textbf{80 m}\\\end{array}\\\textbf{PV = 80 m}[/tex]

2. Distance travelled by Pedro

Distance = PV + VS + SE = 80 m + 160 m + 100 m = 340 m

Pedro walks 340 m to school.

Compute 8P2 *
16
O 56
O 28
O
none of these are correct

Answers

it’s none of these, the answer is 0.

find the area of this figure to the nearest hundredth use 3.14 to approximate pi A=? ft squared

Answers

Answer:

[tex]105.13ft^2[/tex]

Step-by-step explanation:

Rectangle

[tex]A=lw\\=10*8\\=80ft^2\\[/tex]

Semicircle

[tex]A=\frac{1}{2} \pi r^2\\=\frac{1}{2}* \pi *4^2\\=25.13ft^2[/tex]

Add both values together

[tex]80+25.13\\=105.13ft^2[/tex]

Answer: 105.13

Step-by-step explanation:

Idaho is shaped like a triangle with a base of approximately 320 miles and a height of approximately 520 miles. Calculate the area of Idaho and write the answer in scientific notation

Answers

Answer:

8.32 × 10^4

Step-by-step explanation:

The formula for the area of a triangle is 1/2×b×h.

1/2(320)(520) = 83,2000

83,200 in scientific notation is 8.32 × 10^4

Please answer this correctly

Answers

Answer:

342 square meters

Step-by-step explanation:

Consider the length of j;

[tex]j * 9 * 9 = 405,\\j = 405 / 81,\\j = 5 meters[/tex]

Applying the volume of a rectangular prism formula length * width * height = volume, we noted that 9, 9, and j corresponded to the length, width, and height of the rectangular prism and made it equivalent to the volume. Doing so, we solved for j. Now let us solve for the surface area;

[tex]Area of 1st Face = 5 * 9 = 45,\\Area of 2nd Face = 9 * 9 = 81,\\Area of 3rd Face = 5 * 9 = 45,\\\\Surface Area = 2 * ( 45 ) + 2 * ( 81 ) + 2 * ( 45 ) = 342 square meters[/tex]

Opposite faces are equal in terms of their area, so by finding the area of 3 faces, we multiply their area each by 2 to result in the total surface area!

Ronald needs a morning breakfast drink that will give him at least 390 calories. Orange juice has 130 calories in 8oz. How many ounces does he need to drink to reach his calorie goal?

Answers

Answer:

24 ounces of orange juice

Step-by-step explanation:

Given-

          Calories needed=390 calories

    Calories in 8oz juice=130 calorie

Therefore ounces of juice=(390/130)8

                                          =3 x 8

                                          =24 ounces

If Ronald needs a morning breakfast drink that will give him atleast 390 calories. Orange juice has 130 calories in 8oz. Then 24 ounces does he need to drink to reach his calorie goal.

What is Equation?

Two or more expressions with an Equal sign is called as Equation.

Ronald needs a morning breakfast drink that will give him at least 390 calories.

Orange juice has 130 calories in 8oz.

We need to find how many ounces does he need to drink to reach his calorie goal

Calories needed=390 calories

Calories in 8oz juice=130 calorie

Three hundred ninety divided by one hundred thirty times of eight.

Therefore ounces of juice=(390/130)8

Three hundred ninety divided by one hundred thirty is three.

=3 x 8

Three times of eight is twenty four.

=24 ounces

Hence 24 ounces of orange juice does he need to drink to reach his calorie goal.

To learn more on Equation:

https://brainly.com/question/10413253

#SPJ2

Please help me HURRY!!!!!!

Answers

K=-2 because the other answers are greater than -2 and the answer has to be less than or equal to

One angle of a right triangle measures 51 degrees. What is the measure of the other small angle?

Answers

Answer:

a rigt angle is a total of 90 degrees so subtratct 51 from 90 and you get 39 degrees.

The people at the party ate 16 chocolate chip cookies and 26 sugar cookies. What percent of the cookies were sugar cookies?

Answers

Answer:

61%

Step-by-step explanation:

16/26 x 100 = 61.538461

You have to round it up if the question tells you to round it up.

hope it helps! :)

Answer:

62%

Step-by-step explanation:

42 x 62% = 26.04

I am sorry if you get this wrong. I really hope this helps.

I need help with this questions

Answers

i believe it is the first one.

Answer:

The second choice.

Step-by-step explanation:

a newborn calf weighs 40 kilograms. Each week its weight increases by 5%. Let W be the weigh in kilograms of the calf after t weeks

Answers

3 I’m pretty sure but hey idk

Suppose parts are of two varieties: good (with probability 90/92) and slightly defective (with probability 2/92). Parts are produced one after the other. What is the probability that at least 3 parts must be produced until there is a slightly defective part produced

Answers

Answer:

95.69%

Step-by-step explanation:

We have X is the number of parts produced up to (and including) the first slightly defective part. So, X is Geometric (2/92), which would be the following:

P (X => 3) = Summation i = 3, up to infinity of {[(90/92)^(i-1)] * (2/92)}

We replace and solve and we are left with:

P (X => 3) = (2/92) * (90/92)^(3-1) * 1/(1 - 90/92)

P (X => 3) = 0.9569

Which means that the probability that at least 3 parts must be produced until there is a slightly defective part produced is 95.69%

HELP! the function f(x)=200/x+10 models the cost per student of a field trip when x students go on the trip. how is the parent function f(x)=1/x transformed to create the function f(x)=200/x+10

Answers

Answer:

stretch of 200 shift up 10 units

Step-by-step explanation:

f(x)=1/x to 200/x+10

Multiply by 200 means a stretch of 200

f(x) = 200/x

Now shift up 10 units

f(x) = 200/x + 10

Answer:

It moves up 10 units

Step-by-step explanation:

f(x) =1/x to 200/x + 10

= 200/x

If we shift up 10 units, we get:

f(x) = 200/x + 10

Hope this helps!

Classify the following triangle .check all that apply

Answers

Answer:

Its right and scalene.

It has a right angle and all the sides are diferent.

Which of the following rational numbers is greater than 5/17 but less than 6/17.

Answers

Answer:

[tex]\frac{51}{170},\ \frac{52}{170},\frac{53}{170},...................\ \frac{59}{170}[/tex]

Step-by-step explanation:

As mention in the question number is

[tex]\frac{5}{17}\ < \frac{6}{17} \\multiply\ both\ side\ by\ 10\ in\ numerator\ and\ denominator\ we\ get \\\frac{50}{170} <\frac{60 }{170}\\[/tex]

Therefore the number is :

[tex]\frac{51}{170},\ \frac{52}{170},\frac{53}{170},...................\ \frac{59}{170}[/tex]

If a number is added to the numerator of 7/9 and the same number is subtracted from the denominator, the result is 3. Find the number.

Answers

Answer:

5

Step-by-step explanation:

[tex]\frac{7+x}{9-x}=3\\ 7+x = 3(9-x)\\7+x=27-3x\\x+3x=27-7\\4x=20\\x=5[/tex]

What’s the correct answer for this?

Answers

the answer would be 13.9 kg of gravel used per square meter

Answer:

B.

Step-by-step explanation:

In the attached file

(TEKS 2A.) EF has midpoint M (6,2) and F (12,-6). What is the coordinates of the endpoint E.
A (2,8)
C (0, 10)
B (18,-2)
D (18,-14)

Answers

Answer:

C (0, 10)

Step-by-step explanation:

The point E is (x,y)

The point F is (12,-6).

The midpoint between E and F is M(6,2).

Midpoint

Is the mean between the points of E and F.

x

[tex]\frac{x + 12}{2} = 6[/tex]

[tex]x + 12 = 12[/tex]

[tex]x = 0[/tex]

y

[tex]\frac{y - 6}{2} = 2[/tex]

[tex]y - 6 = 4[/tex]

[tex]y = 10[/tex]

So E(0, 10), which means that the correct answer is C.

Pythagorean theorem please help

Answers

Answer:

4√73

Step-by-step explanation:

x^2= 12^2 + 32^2

x^2= 144+ 1024

x^2=1168

x= 4√73

ASAP! GIVING BRAINLIEST! Please read the question THEN answer CORRECTLY! NO guessing. I say no guessing because people usually guess on my questions.

Answers

Answer:

A

Step-by-step explanation:

It is not B because 7x^2 means multiplying the equation by seven. It isn't C because that would move the graph DOWN seven units. And it's not D because when it is in parenthesis like that, it means that it is a horizontal shift, not vertical.

Answer:

A. G(x) = [tex]x^2+7[/tex]

Step-by-step explanation:

→For the function to shift upwards 7 units, 7 must be added to the function, like so:

G(x) = [tex]x^2+7[/tex]

→F(x) + c (in this case is 7), cases a vertical shift and the function is moved "c," units. The graph would shift downwards if 7 was being subtracted.

This means the correct answer is A.

Calculating the standard deviation (σ) for a list of n data values: 1. Calculate the average value. 2. Subtract the average value from each individual data value and enter the results in a column to the right of the data values. 3. Square each of the results obtained in step 2, and enter these in a new column to the right. 4. Sum the squares obtained in step 3. 5. Divide the result from step 4 by (n - 1) (the total number of measurements minus 1). 6. Take the square root of the result from step 5. This is the standard deviation. Expressed as an equation, the standard deviation of n measurements of data value x is: σ = ( Σ (x - xavg)2 / (n - 1) )1/2 Using the 6 steps above (or the spreadsheet function), calculate the standard deviation for the six values on page 16 and enter your answer below. Enter your result with only one sig fig, and remember to use a zero before the decimal point for values less than 1, for example 0.05 or 0.01.

Answers

Answer:

Step-by-step explanation:

The missing list of the data values for the question are as follows:

1             1.03

2             1.01

3             0.96

4             0.96

5             0.99

6             1

7             1.01

8             0.98

9             1.02

10            1.03

11             1

12             0.99

13             1

14             0.97

15             1.01

               [tex]x_i[/tex]                          [tex](x_i - \bar x)[/tex]                              [tex](x_i - \bar x)^2[/tex]

1             1.03                         0.03                                  0.0009

2             1.01                         0.01                                   0.0001

3             0.96                        -0.4                                   0.0016

4             0.96                        -0.4                                   0.0016

5             0.99                        -0.1                                   0.0001

6             1                               0.0                                   0.0

7             1.01                           0.1                                   0.0001

8             0.98                        -0.2                                   0.0004

9             1.02                          0.2                                   0.0004

10            1.03                          0.3                                   0.0009

11             1                               0.0                                   0.0

12             0.99                        -0.1                                   0.0001

13             1                               0.0                                   0.0

14             0.97                        -0.03                                   0.0009

15             1.01                           0.1                                   0.0001

The average value for x is calculated as:

[tex]\bar x = \dfrac{14.96}{15}[/tex]

[tex]\bar x = 0.997 \\ \\ \bar x \approx 1.00[/tex]

[tex]\sum (x-x_i)^2 = 0.0072[/tex]

[tex]\dfrac{\sum (x-x_i)^2 }{n-1}= \dfrac{0.0072}{15-1} \\ \\ = \dfrac{0.0072}{14} \\ \\ = 0.00051[/tex]

[tex]\sigma = \sqrt{\dfrac{\sum (x-x_i)^2 }{n-1}} = \sqrt{0.00051} \\ \\ \sigma =0.0226 \\ \mathbf { \\ \sigma =0.02 \ to \ one \ significant \ figure}[/tex]

Can you help me with this one don’t get it

Answers

Answer: 95

Do you need an explication?
Answer : 95
The total degrees of angles is (n-2) *180
And since there are 5 sides it’s 3 *180 which gives u 540. Then you subtract all the given angles or find the remaining angle

In a sample of 800 adults, 214 think that most celebrities are good role models. Two us adults are selected from this sample without replacement. find the probability that both adults think most celebrities are good role models

Answers

Answer:

11449/160000

Step-by-step explanation:

The probability of selecting a single adult that thinks most celebrities are good role models is 214/800 = 107/400

The probability that both do is

(107/400)^2 =. 11449/160000

Solve the equation A = bh for b.

b = Ah

b = A/h

b = h/A

b = h – A

Answers

Answer:

A/h = b

Step-by-step explanation:

A = bh

Divide each side by h

A/h = bh/h

A/h = b

Answer:

[tex]b=\frac{A}{h}[/tex]

Step-by-step explanation:

→To get "b," by itself, all you need to do is divide both sides by "h," like so:

[tex]A=bh[/tex]

[tex]\frac{A}{h} =\frac{bh}{h}[/tex]

[tex]\frac{A}{h} = b[/tex]

if a propane tank has the shape of a cylindrical tank with a height of 4.2m and a radius of 1.3m how many cubic metres of propane is in the tank if it's only 50% full

Answers

Answer:

11.1 cm³

Step-by-step explanation:

V=πr²h / 2 (for half full)

V = (3.14)(1.3)²(4.2)/2

V = 11.1 cm³

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Use evidence from the text to support your response. Your response should be two or three complete paragraphs. A political analyst believes that a senator's recent decision to support a bill resulted in a drop of approval ratings. To test this claim, he selects random cities in the state that voted the senator in and compares the approval ratings before the decision to the approval ratings after the decision. Suppose that data were collected for a random sample of 8 cities, where each difference is calculated by subtracting the percent approval rating before the decision from the percent approval rating after the decision. Assume that the percentages are normally distributed. What type of test is this hypothesis test? If a patient needs a 30-day supply of tablets four times a day, how many tablets will the patient need for discharge? Simplify expression. Use the distributive property. :)14-2(4x+3y) Please answer correctly !!!!!!! Will mark brianliest answer !!!!!!!!!! an increase in the velocity of money will lead to The main() module in the starter code below takes integar inputs separated by commas from the user and stores them in a list. Then, it allows the user to manipulate the list using 3 functions:mutate_list() takes 3 parameters -- a list, index number, and a value -- and inserts the value in the position specified by the index number in the list.remove_index() takes 2 parameters -- a list and an index number -- and remove the element at the position number indicated by index. It also prints the total number of elements in the list before and after removing the character in this fashion:"Total elements in list = 11Total elements in list = 10"reverse_list() takes 1 parameter -- a list -- and returns the list reversed.Examples:Example 1:Enter values in list separated by commas: 1,2,4,63,6,4,22,53,76[1, 2, 4, 63, 6, 4, 22, 53, 76]Menu:mutate list(m), remove (r), reverse_list (R)Enter choice (m,r,R): m4,45[1, 2, 4, 63, 45, 6, 4, 22, 53, 76]Example 2:Enter values in list separated by commas: 1,2,4,6,84,3,2,2,76[1, 2, 4, 6, 84, 3, 2, 2, 76]Menu:mutate list(m), remove (r), reverse_list (R)Enter choice (m,r,R): R[76, 2, 2, 3, 84, 6, 4, 2, 1]Example 3:Enter values in list separated by commas: 12,2,3,5,2,6,2,1,2,333,65[12, 2, 3, 5, 2, 6, 2, 1, 2, 333, 65]Menu:mutate list(m), remove (r), reverse_list (R)Enter choice (m,r,R): rExample 4Total elements in list = 11Total elements in list = 10[12, 2, 3, 5, 6, 2, 1, 2, 333, 65]please use the codes belowdef main():user_list = input("Enter values in list separated by commas: ")user_list = user_list.split(",")user_list = [int(i) for i in user_list]print(user_list)print("Menu: ")print("mutate list(m), remove (r), reverse_list (R)")user_choice = input("Enter choice (m,r,R): ")if user_choice == 'm':index_num, v = input().split(",")index_num = int(index_num)v = int(v)mutate_list(user_list, index_num, v)print(user_list)elif user_choice == 'r':index_num = int(input())remove_index(user_list, index_num)print(user_list)elif user_choice == 'R':new_list = reverse_list(user_list)print(new_list)main()