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

e
65. the perpendicular
bisector of the
segment with
endpoints (-5/2,-2)
and (3, 5)
HELP PLEASE! Picture included!

Answers

Answer:

  44x +56y = 95

Step-by-step explanation:

To write the equation of the perpendicular bisector, we need to know the midpoint and we need to know the differences of the coordinates.

The midpoint is the average of the coordinate values:

  ((-2.5, -2) +(3, 5))/2 = (0.5, 3)/2 = (0.25, 1.5) = (h, k)

The differences of the coordinates are ...

  (3, 5) -(-2.5, -2) = (3 -(-2.5), 5 -(-2)) = (5.5, 7) = (Δx, Δy)

Then the perpendicular bisector equation can be written ...

  Δx(x -h) +Δy(y -k) = 0

  5.5(x -0.25) +7(y -1.5) = 0

  5.5x -1.375 +7y -10.5 = 0

Multiplying by 8 and subtracting the constant, we get ...

  44x +56y = 95 . . . . equation of the perpendicular bisector

The temperature in a town is −2.7°C. The temperature decreases 3°C. What is the new temperature? Incorrect

Answers

Answer:

-5.7° C

Step-by-step explanation:

-2.7 °C (degrees Celsius) - 3 °C (degrees Celsius) = -5.7° C

Help me please the questions are in the picture!!! THX MARK U AS BRAINIEST

Answers

Part A: D=10

Part B: B/12

Answer:

D is 10

b/12

Step-by-step explanation:

What is the area & perimeter of this figure?

Answers

Answer:

The perimeter is

Step-by-step explanation:

perimeter is the whole distance you will go around the shape

Perimeter= 19 +3+(19-5)+(8-3)+5+8

= 19+3+14+5+5+8

= 54

For area, cut the triangle into small and big rectangle

Area = 19 * 3+ (8-3) * 5

= 57 + 25

= 82

What is the approximate value of sin B?
B
>
17.46
7
A
16

Answers

Answer:

Option (B)

Step-by-step explanation:

From the figure attached,

AB = 7 units

BC = 17.46 units

AC = 16 units

Now we apply the sine rule in the given triangle ABC,

SinB = [tex]\frac{\text{Opposite side}}{\text{Hypotenuse}}[/tex]

        = [tex]\frac{AC}{BC}[/tex]

        = [tex]\frac{16}{17.46}[/tex]

        = 0.916

        ≈ 0.92

Therefore, Option (B) will be the answer.

Answer:

DIFFERENT PICS

Step-by-step explanation:

I had one and the awnser was 0.40, and C had a arch whereas B did not.

60 is what percent of 400

Answers

Answer:

15%

Step-by-step explanation:

Is means equals and of means multiply

60 = P * 400

Divide each side by 400

60/400 = P

.15 = P

Change to percent form

15%  is the percent

Answer:

the answer to the question you've asked is 15

Solve the inequality for y.

Answers

-4y ≤ -12

Divide both sides by -4:

y ≤ 3

Because both sides were divided by a negative value you need to reverse the inequality sign:

y ≥ 3

Answer:

y = 3

Step-by-step explanation:

it says -4y ≤ -12 sooooooo    4 x 3 = 12!!!! so y = 3

Mel buys a shirt that cost 12.50 and some pairs of socks that are 2.50 each.He pays a total of 27.50$.How many pairs of socks did Mel buy?

Answers

Answer:

6

Step-by-step explanation:

Let's call the number of pairs of socks he buys s.

[tex]12.50+2.50s=27.50[/tex]

Subtract 12.50 from both sides:

[tex]2.50s=15[/tex]

Divide both sides by 2.5 to isolate s:

[tex]s=6[/tex]

Hope this helps!

Anyone know how to solve this

Answers

Answer:

Y=1800+150x

Step-by-step explanation:

Answer:

4. Y = 150x + 1800  

Sabrina has designed a rectangular painting that measures 65 feet in length and 30 feet in width. Alfred has also designed a rectangular painting, but it measures x feet shorter on each side. When x = 3, what is the area of Alfred's painting?

Answers

Answer:

1674 ft²

Step-by-step explanation:

Area S = 65*30

Area A = (65 - x)(30 - x) = (65 - 3)(30 - 3) = 62*27= 1674 ft²

Assume a simple random sample of 10 BMIs with a standard deviation of 1.186 is selected from a normally distributed population of recent Miss America winners. Use 0.01 significance level to test the claim that the BMI for recent Miss America winners are from a population with standard deviation of 1.34.
A. Identify the null hypothesis and the alternative hypothesis.
B. Find the critical value or values.
C. Find the test statistic.
D. State the conclusion that addresses the original claim.

Answers

Answer:

a) H0: [tex]\sigma = 1.34[/tex]

H1: [tex]\sigma \neq 1.34[/tex]

b) [tex] df = n-1= 10-1=9[/tex]

And the critical values with [tex]\alpha/2=0.005[/tex] on each tail are:

[tex] \chi_{\alpha/2}= 1.735, \chi_{1-\alpha/2}= 23.589[/tex]

c) [tex] t=(10-1) [\frac{1.186}{1.34}]^2 =7.05[/tex]

d) For this case since the critical value is not higher or lower than the critical values we have enough evidence to FAIL to reject the null hypothesis and we can conclude that the true deviation is not significantly different from 1.34

Step-by-step explanation:

Information provided

n = 10 sample size

s= 1.186 the sample deviation

[tex]\sigma_o =1.34[/tex] the value that we want to test

[tex]p_v [/tex] represent the p value for the test

t represent the statistic  (chi square test)

[tex]\alpha=0.01[/tex] significance level

Part a

On this case we want to test if the true deviation is 1,34 or no, so the system of hypothesis are:

H0: [tex]\sigma = 1.34[/tex]

H1: [tex]\sigma \neq 1.34[/tex]

The statistic is given by:

[tex] t=(n-1) [\frac{s}{\sigma_o}]^2 [/tex]

Part b

The degrees of freedom are given by:

[tex] df = n-1= 10-1=9[/tex]

And the critical values with [tex]\alpha/2=0.005[/tex] on each tail are:

[tex] \chi_{\alpha/2}= 1.735, \chi_{1-\alpha/2}= 23.589[/tex]

Part c

Replacing the info we got:

[tex] t=(10-1) [\frac{1.186}{1.34}]^2 =7.05[/tex]

Part d

For this case since the critical value is not higher or lower than the critical values we have enough evidence to FAIL to reject the null hypothesis and we can conclude that the true deviation is not significantly different from 1.34

Write an expression for "the quotient of z and 4

Answers

Answer:

z/4

Step-by-step explanation:

you divide the numerator by the denominator

Answer:

z/4 is the answer

please brainliest me

Step-by-step explanation:

and can me divide which is also (/)

Avantraveling 20 miles per hour can stop in 60 feet. If a van is traveling 32 miles per hour what is it’s stopping distance

Answers

20 mi/60ft can be reduced to 1mi/3ft. So Basically for every mile traveled it takes 3 feet to stop. Therefore 32÷3 = 10.67

Which expression is equivalent to log Subscript 8 Baseline 4 a (StartFraction b minus 4 Over c Superscript 4 Baseline EndFraction)?

Answers

Answer:

[tex]\log_84+\log_8a+\log_8(b-4)-4\log_8c[/tex].

Step-by-step explanation:

The given expression is

[tex]\log_84a\left(\dfrac{b-4}{c^4}\right)[/tex]

Using the properties of logarithm, we get

[tex]\log_84+\log_8a+\log_8\left(\dfrac{b-4}{c^4}\right)[/tex]     [tex][\because \log_a mn=\log_a m+\log_a n][/tex]

[tex]\log_84+\log_8a+\log_8(b-4)-\log_8c^4[/tex]     [tex][\because \log_a \frac{m}{n}=\log_a m-\log_a n][/tex]

[tex]\log_84+\log_8a+\log_8(b-4)-4\log_8c[/tex]     [tex][\because \log_a x^n =n\log_a x][/tex]

Therefore, the required expression is [tex]\log_84+\log_8a+\log_8(b-4)-4\log_8c[/tex].

Answer:

B on edge

Step-by-step explanation:

Length of a rod: Engineers on the Bay Bridge are measuring tower rods to find out if any rods have been corroded from salt water. There are rods on the east and west sides of the bridge span. One engineer plans to measure the length of an eastern rod 25 times and then calculate the average of the 25 measurements to estimate the true length of the eastern rod. A different engineer plans to measure the length of a western rod 20 times and then calculate the average of the 20 measurements to estimate the true length of the western rod.

Answers

Answer:

b. The engineer who weighed the rod 25 times.

Step-by-step explanation:

Hello!

Full text:

Length of a rod: Engineers on the Bay Bridge are measuring tower rods to find out if any rods have been corroded from salt water. There are rods on the east and west sides of the bridge span. One engineer plans to measure the length of an eastern rod 25 times and then calculate the average of the 25 measurements to estimate the true length of the eastern rod. A different engineer plans to measure the length of a western rod 20 times and then calculate the average of the 20 measurements to estimate the true length of the western rod.

Suppose the engineers construct a 90% confidence interval for the true length of their rods. Whose interval do you expect to be more precise (narrower)?

a. Both confidence intervals would be equally precise.

b. The engineer who weighed the rod 25 times.

c. The engineer who weighed the rod 20 times.

X₁: Length of an eastern rod of the Bay Bridge

n₁= 25

X₂: Length of a western rod of the Bay Bridge

n₂= 20

Both Engineers will use their samples to estimate the population average length of the rods using a 90% CI.

Assuming the standard normal distribution, the confidence interval will be centered in the estimated mean.

X[bar] ± [tex]Z_{1-\alpha /2}[/tex]*(σ/√n)

And the width is determined by the semi amplitude:

↓d= [tex]Z_{1-\alpha /2}[/tex]*(σ/√↑n)

As you can see the sample size has an indirect relationship with the semi amplitude of the interval. This means, when the sample size increases, the semi amplitude decreases, and if the sample size decreases, the semi amplitude increases. Naturally this is leaving all other elements of the equation constant, this means, using the same confidence level and the same population standard deviation.

Since the first engineer took the larger sample, he's confidence interval will be narrower and more accurate.

Hope this helps!

If Romeo earns 8% more than Juliet, Romeo’s salary is how many times Juliets salary?
A) 1.08
B) 0.92
C) 80
D) 108

Answers

Answer:

1.08

Step-by-step explanation:

If Romeo earns 8% more than Juliet,

Example?

If Juliet earns $80

80x8% = 6.40  So his pay would be 80 + 6.40

If you times 80 by 1.08 (this would also be 108%) you would get $86.40

Use z scores to compare the given values. Based on sample​ data, newborn males have weights with a mean of 3259.6 g and a standard deviation of 722.4 g. Newborn females have weights with a mean of 3031.2 g and a standard deviation of 495.9 g. Who has the weight that is more extreme relative to the group from which they​ came: a male who weighs 1700 g or a female who weighs 1700 ​g? Since the z score for the male is zequals nothing and the z score for the female is zequals nothing​, the female female male has the weight that is more extreme.

Answers

Answer:

Since the z score for the male is z=-2.1589 and the z score for the female is z=-2.6844​, the female has the weight that is more extreme.

Step-by-step explanation:

To find the z score, we use the following equation:

[tex]z=\frac{x-m}{s}[/tex]

Where m is the mean and s is the standard deviation.

So, the z score for a male who weighs 1700 g is:

[tex]z=\frac{1700-3259.6}{722.4}=-2.1589[/tex]

At the same way, the z score for a female who weighs 1700 g is:

[tex]z=\frac{1700-3031.2}{495.9}=-2.6844[/tex]

Finally, -2.6844 is farther from zero than -2.1589, so the female has the weight that is more extreme.

resuelve las siguientes ecuaciones tales que 0° ≤ x ≤ 360°
sen x=sen (π/2-x)
cos x + 2 sen x= 2
csc x = sec x
2 cos x * tan x -1 = 0
4 cos2 x = 3 - 4 cos x

Answers

Answer:

4cos=2X

X=3-4COS

X=-1

Please help me. I’ll mark you as brainliest if correct

Answers

Answer:

b = -18

Step-by-step explanation:

(3 + 4i) (-3-2i)

When we foil:

-9 + -6i + -12i + -8i^2

-8i^2 = +8

Combine like terms:

-1 + -18i

Find the value of z

Answers

Answer:

87°

Step-by-step explanation:

In the given figure, a quadrilateral is inscribed in a circle. Therefore, it is a cyclic quadrilateral.

Opposite angles of a cyclic quadrilateral are supplementary.

[tex] \therefore \: z + 93 \degree = 180 \degree \\ \therefore \: z = 180 \degree - 93 \degree \\ \huge \red{ \boxed{\therefore \: z = 87 \degree}}[/tex]

YOU KNOW THE DRILL 2.0

Answers

Answer:

#1

Step-by-step explanation:

The four yellow boxes represent x so together they are 4 * x or 4x. The blue boxes seem to represent -1 and since there are three of them together they are -1 * 3 = -3. 4x + (-3) = 4x - 3.

A 120-gallons (gal)tank initially contains 90 lb of a salt dissolved in 90 gal of water. Brine containing 2 lb/gal of salt flows into the tank at the rate of 4gal/min. The mixture is kept uniform by stirring, and the stirred mixture flows out at the rate of 3gal/min. How much salt does the tank contain when it is full

Answers

Answer:

The tank will contain 202 Ib of salt when it's full.

Step-by-step explanation

To find the amount of salt in the tank at time t= x(t)

If x(0)= 90Ib

To find the volume of the tank at time t

V(t)= 90+(4-3)t=90+t gal

Other solutions are found attached

For circle O, and m∠ABC = 55°. In the figure, ∠ and ∠ have measures equal to 35°.

Answers

Answer:

In the figure ∠ABO and ∠BCO have measures equal to 35°.

Step-by-step explanation:

Measure of arc AD = 180-measure of arc CD= 180-125 =55

m<AOB= 55 ( measure of central angle is equal to intercepted arc)

<OAB= 90 degrees (Tangent makes an angle of 90 degrees with the radius)

In triangle AOB ,

< AB0 = 180-(90+55)= 35 degrees( angle sum property of triangle)

In triange BOC ,< BOC=125 ,

m<, BCO=35 degrees

Answer:

∠ABO and ∠BCO

Step-by-step explanation:

Which are steps that could be used to solve 0 = 9(x2 + 6x) – 18 by completing the square? Check all that apply. 18 + 81 = 9(x2 + 6x + 9) 18 + 9 = 9(x2 + 6x + 9) 18 + 36 = 9(x2 + 6x + 36) 11 = (x + 3)2 StartRoot 342 EndRoot = (x + 6)2 StartRoot 99 EndRoot = (x + 3)2

Answers

Answer:

18 + 81 = 9(x² + 6x + 9)

11 = (x + 3)²

When we are completing the square, we are going to move the value of c across the equals.  We will do that by adding, and end up with

18=9(x²+6x)

We take the value of b (the coefficient of x), divide it by 2 and square it:

(6/2)²=3²=9

This is the value that completes the square.  However, since the entire square is multiplied by 9, this value must be multiplied by 9 before we can add it across the equals:

18+9(9) = 9(x²+6x+9)

18+81=9(x²+6x+9)

99=9(x²+6x+9)

Dividing both sides by 9, we have:

11=x²+6x+9

11=(x+3)²

Answer:

18 + 81 = 9(x2 + 6x + 9) and 11 = (x + 3)2

Step-by-step explanation:

EDG

What measures of the cylinder do 12 and 42 describe?

A cylinder with height of 42 millimeters and radius of 12 millimeters.
radius and diameter
radius and height
diameter and height
diameter and area of base

Answers

Answer: radius and height

Step-by-step explanation:

Radius is the distance between the center of the circle to its boundary.

Height is the length of the figure from top to bottom.

Given statement : A cylinder with height of 42 millimeters and radius of 12 millimeters.

That clearly means that the cylinder is having radius of 12 millimeters i.e. 12 is representing the measure of the radius of the cylinder.

And Similarly, 42 is representing the measure of the height of the cylinder.

Hence, the 2 and 42 describe the radius and height respectively of the cylinder.

Answer:

radius and height

Step-by-step explanation:

i just took the test edge 2020. rate me 5 stars!

Q 2.20: In a survey, there are two categories of respondents, employed and unemployed people, and two options, A and B. The proportion of those who have chosen option B is greater than 0.5 among the total number of the respondents, but is lower than 0.5 among the unemployed respondents. We know that 314 employed and 512 unemployed people chose option A and 356 employed chose option B. How many unemployed people chose option B

Answers

Answer:

The answer is 508

Step-by-step explanation:

Solution

First of all, the proportion of B is exceeds 0.5 in total.

Now,

To find the total of A it we have A =314 +512 = 826

The number of employed that choose B = 356

For us to have the proportion of B to be higher than the 0.5, the unemployed B from what is shown here should exceed the difference between total A and B employed

what this suggest is that the employed B is greater than 826-356 = 470

So,

The respondent that are unemployed that choose B  must be greater than 470

Thus,

We recall that the B proportion among the unemployed respondent is lesser than .50

Thus suggests that the respondent that are unemployed who choose be is lesser than 512

The conditions becomes

470 lesser than the number of unemployed respondents who selected B lesser than 512

Hence  the needed number of the number of unemployed respondents who chose B should be between 470 and 512

So, possible answer here is 508.

What sequence is generated by the function f(n+1)=f(n)-2 for f(1)=10

Answers

Answer:

-3

Step-by-step explanation:

6x +7y=-46 3x-2y=32 solve this system of linear equations

Answers

Hello

We have two equations and need to find x and y

(1) 6x+7y=-46

(2) 3x-2y=32

multiply (2) by 2 it gives

(2') 6x-4y=64

(1) - (2') gives

6x+7y-6x+4y=-46-64 = -110

so 11y = -110

y = -10

replace in (2) it gives

3x+20=32

3x=12

x = 12/3 = 4

the solution is (4,-10)

do not hesitate if you need further explanation

if you like my answer, tag it as the brainliest :-)

Find the 1000th term for the sequence

Answers

Answer:

D. 7017

Step-by-step explanation:

if 24 is the first term, find 7x999, or 7x1000-7 and add 24

however a better way would be to use the formula

value=a+(n-1)d

a = the first term in the sequence (24)

n     =     the amount of terms you need (1000)

d = the common difference between terms (7)

URGERNT!!!PLS AT LEAST TAKE A LOOK!!! SHARE YO SMARTNESSS!! AND BLESS YOUR GRADES!

Which sign explains the relationship between m∠1 and m∠2 in the diagram?
A) not equal to
B) >
C) <
D) =

Answers

Answer:

Dear Laura Ramirez

Answer to your query is provided below

Option D is correct.

Reason - Because of Hinge and Converse of Hinge theorem

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