Each side of a square is increasing at a rate of 4 cm/s. At what rate (in cm2/s) is the area of the square increasing when the area of the square is 25 cm2
Answer:
The area of the square is increasing at a rate of 40 square centimeters per second.
Step-by-step explanation:
The area of the square ([tex]A[/tex]), in square centimeters, is represented by the following function:
[tex]A = l^{2}[/tex] (1)
Where [tex]l[/tex] is the side length, in centimeters.
Then, we derive (1) in time to calculate the rate of change of the area of the square ([tex]\frac{dA}{dt}[/tex]), in square centimeters per second:
[tex]\frac{dA}{dt} = 2\cdot l \cdot \frac{dl}{dt}[/tex]
[tex]\frac{dA}{dt} = 2\cdot \sqrt{A}\cdot \frac{dl}{dt}[/tex] (2)
Where [tex]\frac{dl}{dt}[/tex] is the rate of change of the side length, in centimeters per second.
If we know that [tex]A = 25\,cm^{2}[/tex] and [tex]\frac{dl}{dt} = 4\,\frac{cm}{s}[/tex], then the rate of change of the area of the square is:
[tex]\frac{dA}{dt} = 2\cdot \sqrt{25\,cm^{2}}\cdot \left(4\,\frac{cm}{s} \right)[/tex]
[tex]\frac{dA}{dt} = 40\,\frac{cm^{2}}{s}[/tex]
The area of the square is increasing at a rate of 40 square centimeters per second.
Joe's Auto Insurance Company customers sometimes have to wait a long time to speak to a
customer service representative when they call regarding disputed claims. A random sample
of 25 such calls yielded a mean waiting time of 22 minutes with a standard deviation of 6
minutes. Construct a 95% and 99% confidence interval for the population mean of such
waiting times. Explain what these interval means.
Answer:
The 95% confidence interval for the population mean of such waiting times is between 19.5 and 24.5 minutes. This means that we are 95% sure that the true mean waiting time of all calls for this company is between 19.5 and 24.5 minutes.
The 99% confidence interval for the population mean of such waiting times is between 18.6 and 25.4 minutes. This means that we are 99% sure that the true mean waiting time of all calls for this company is between 18.6 and 25.4 minutes.
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 25 - 1 = 24
95% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 24 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.95}{2} = 0.975[/tex]. So we have T = 2.0639
The margin of error is:
[tex]M = T\frac{s}{\sqrt{n}} = 2.0639\frac{6}{\sqrt{25}} = 2.5[/tex]
In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 22 - 2.5 = 19.5 minutes
The upper end of the interval is the sample mean added to M. So it is 22 + 2.5 = 24.5 minutes
The 95% confidence interval for the population mean of such waiting times is between 19.5 and 24.5 minutes. This means that we are 95% sure that the true mean waiting time of all calls for this company is between 19.5 and 24.5 minutes.
99% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 24 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.99}{2} = 0.995[/tex]. So we have T = 2.797
The margin of error is:
[tex]M = T\frac{s}{\sqrt{n}} = 2.797\frac{6}{\sqrt{25}} = 3.4[/tex]
In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 22 - 3.4 = 18.6 minutes
The upper end of the interval is the sample mean added to M. So it is 22 + 3.4 = 25.4 minutes
The 99% confidence interval for the population mean of such waiting times is between 18.6 and 25.4 minutes. This means that we are 99% sure that the true mean waiting time of all calls for this company is between 18.6 and 25.4 minutes.
Geometry PLS HELP due soon
Answer:
(3) [tex]x = 7.5[/tex] and [tex]y = 51[/tex]
(4) [tex]x = 6[/tex]
Step-by-step explanation:
Question 3
Required
Solve for x and y
We have:
[tex]16x - 18 + 10x +3 = 180[/tex] --- angle on a straight line
Collect like terms
[tex]16x + 10x = 180 + 18 - 3[/tex]
[tex]26x = 195[/tex]
Solve for x
[tex]x = 195/26[/tex]
[tex]x = 7.5[/tex]
Also:
[tex]16x - 18 = 2y[/tex] ---- opposite angles
So, we have:
[tex]16 * 7.5 - 18 = 2y[/tex]
[tex]120 - 18 = 2y[/tex]
[tex]102 = 2y[/tex]
Divide by 2
[tex]51 = y[/tex]
[tex]y = 51[/tex]
Question 4:
Required
Solve for x
We have:
[tex]11x - 2 + 5x - 4 = 90[/tex] ---- angle at right-angled
Collect like terms
[tex]11x + 5x = 90 +2 + 4[/tex]
[tex]16x = 96[/tex]
Divide by 16
[tex]x = 6[/tex]
Find a linear function that models the cost, C, to produce x toys given the rate of change and initial output value. The cost to produce plastic toys increases by 90 cents per toy produced. The fixed cost is 40 dollars. C(x) = dollars Write a linear model for the amount of usable fabric sheeting, F, manufactured in t minutes given the rate of change and initial output value. Fabric sheeting is manufactured on a loom at 7.25 square feet per minute. The first five square feet of the fabric is unusable. F(t) = ft^2 is the amount of usable fabric sheeting manufactured in t minutes.
Answer:
C(x) = $40 + 0.9x
F(t) = 7.25t - 5
Step-by-step explanation:
Given that :
C(x) = Cost model to produce x toys
Fixed cost of production = $40
Rate of change = 90 cent per toy produced.
A linear model will take the form :
F(x) = bx + c ;
Where ; b = rate of change or slope ; c = intercept or initial value
Therefore, a linear cost model will be :
Cost model to produce x toys = fixed cost + (rate of change * number of toys)
C(x) = $40 + 0.9x
2.)
F(t) = amount of usable factory sheets manufactured in t minutes :
Rate of production = 7.25 ft² / minute
Number of unusable fabric sheeting = 5 ft²
The function, F(t) :
F(t) = 7.25t - 5
At a hockey game, a vender sold a combined total of 228 sodas and hot dogs. The number of sodas sold was two times the number of hot dogs sold. Find the number of sodas and the number of hot dogs sold.
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Answer:
152 sodas76 hot dogsStep-by-step explanation:
Of the items sold, sodas were 2/(2+1) = 2/3 of the total.
(2/3)(228) = 152 . . . sodas were sold
152/2 = 76 . . . . hot dogs were sold
Which statement must be true if APQR = ASTU?
Answer:
(a) [tex]PQ \sim ST[/tex]
Step-by-step explanation:
Given
See attachment
Required
Which must be true
[tex]\triangle PQR \simeq \triangle STU[/tex] implies that:
The following sides are corresponding
[tex]PQ \sim ST[/tex]
[tex]PR \sim SU[/tex]
[tex]QR \sim TU[/tex]
The following angles are corresponding
[tex]\angle P \sim \angle S[/tex]
[tex]\angle Q \sim \angle T[/tex]
[tex]\angle R \sim \angle U[/tex]
From the given options, only option (a) is true because:
[tex]PQ \sim ST[/tex]
The cost of renting a car is $46/week plus $0.25/mile traveled during that week. An equation to represent the cost would be y = 46 + 0.25x, where x is the number of miles traveled.
what is your cost if you travel 59 miles
cost: 60.75
if your cost Is $66.00, how many miles were you charged for traveling?
miles: ?
you have a max of $100 to spend on a car rental. what would be the maximum number of miles you could Travel?
max miles: ?
Answer:
If your cost Is $66.00, how many miles were you charged for traveling?
y = cost = $66[tex]66=46+0.25x\\66-46=0.25x\\20=0.25x\\x=\frac{20}{0.25} =80[/tex]80 miles
You have a max of $100 to spend on a car rental. what would be the maximum number of miles you could Travel?
y = cost = $100[tex]100=46+0.25x\\100-46=0.25x\\54=0.25x\\x=\frac{54}{0.25} =216[/tex]216 miles
HELPPP PLEASEEE! I tried everything from adding to dividing, subtracting, multiplying but still no correct answer. Can someone help me out here please? I am not sure where to start either now. Thank you for your time.
Solve by graphing. Round each answer to the nearest tenth.
6x2 = −19x − 15
a: −2, 1.7
b: −1.7, −1.5
c: −1.5, 1.5
d: −1.5, 1.7
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Answer:
b: -1.7, -1.5
Step-by-step explanation:
The graph is shown below. We have annotated the x-intercepts for the equivalent equation ...
6x^2 +19x +15 = 0
In a certain region, the probability of a baby being born a is instead of 0.5. Let A denote the event of getting a when a baby is born. What is the value of ?
Answer:
[tex]P(\bar A) = 0.5[/tex]
Step-by-step explanation:
Given
[tex]P(A) = 0.5[/tex]
Required
[tex]P(\bar A)[/tex]
To do this, we make use of complement rule:
[tex]P(\bar A) = 1 - P(A)[/tex]
So, we have:
[tex]P(\bar A) = 1 - 0.5[/tex]
[tex]P(\bar A) = 0.5[/tex]
Cho hàm số f(x, y) = ln(x
2 + y
2
).
a) Tính f
′
x
, f′
y
;
b) Tính f
′
x
(2; 1), f′
y
(2; 1).
Answer:
Sorry, I can't understand in which language you have written......
Step-by-step explanation:
So if you tell me the question in English then I can answer
What is the minimum of y=1/3 x^2 + 2x + 5
Answer:
min at x = -3
Step-by-step explanation:
steps are in the pic above.
Round your number to the nearest hundredth 65 7
51
What is the inverse of the function f(x) = 2x + 1?
Oh(x) =
1
2x-
o h«x)= kx +
- 3x-2
Oh(x) =
Oh(x) =
Mark this and return
Save and Exit
Next
Submit
Type here to search
81
O
10:49 AM
^ D 0x
mamman
Answer:
let inverse f(x) be m:
[tex]m = \frac{1}{2x + 1} \\ 2x + 1 = \frac{1}{m} \\ 2x = \frac{1 - m}{m} \\ x = \frac{1 - m}{2m} [/tex]
substitute x in place of m:
[tex]{ \bf{ {f}^{ - 1}(x) = \frac{1 - x}{2x } }}[/tex]
Nellie prepares 2 kilograms of dough every hour she works at the bakery. How many hours
did Nellie work if she prepared 6 kilograms of dough?
2 kg dough = 1 hour
1 kg dough = 1 hour/2 = 1/2 hour
6 kg dough = 6 × (1/2 hour) = 6/2 hours = 3 hours
Answer: 3 hours
Step-by-step explanation: x represents the number of hours she works
2x=6
x=6/2
x=3
An employee at a shoe store has observed that taller customers have larger shoe sizes than customers who are shorter. She knows that shoe sizes are based on foot length, so she hypothesizes: Compared with shorter people, taller people have longer feet.
Question attachment below
Answer and explanation:
Data patterns are repeated data occurrences in a certain way that is recognizable.
In the example below, the data pattern shows taller people require larger shoe sizes(the taller the person the larger the shoe size) but does make some exceptions. Example: while Denver is taller and requires a larger shoe size, Eduardo is shorter than Tim and still requires a larger shoe size than Tim.
If V= {i}, subset of V are?
Answer:
Defintion. A subset W of a vector space V is a subspace if
(1) W is non-empty
(2) For every v, ¯ w¯ ∈ W and a, b ∈ F, av¯ + bw¯ ∈ W.
Expressions like av¯ + bw¯, or more generally
X
k
i=1
aiv¯ + i
are called linear combinations. So a non-empty subset of V is a subspace if it is
closed under linear combinations. Much of today’s class will focus on properties of
subsets and subspaces detected by various conditions on linear combinations.
Theorem. If W is a subspace of V , then W is a vector space over F with operations
coming from those of V .
In particular, since all of those axioms are satisfied for V , then they are for W.
We only have to check closure!
Examples:
Defintion. Let F
n = {(a1, . . . , an)|ai ∈ F} with coordinate-wise addition and scalar
multiplication.
This gives us a few examples. Let W ⊂ F
n be those points which are zero except
in the first coordinate:
W = {(a, 0, . . . , 0)} ⊂ F
n
.
Then W is a subspace, since
a · (α, 0, . . . , 0) + b · (β, 0, . . . , 0) = (aα + bβ, 0, . . . , 0) ∈ W.
If F = R, then W0 = {(a1, . . . , an)|ai ≥ 0} is not a subspace. It’s closed under
addition, but not scalar multiplication.
We have a number of ways to build new subspaces from old.
Proposition. If Wi for i ∈ I is a collection of subspaces of V , then
W =
\
i∈I
Wi = {w¯ ∈ V |w¯ ∈ Wi∀i ∈ I}
is a subspace.
Proof. Let ¯v, w¯ ∈ W. Then for all i ∈ I, ¯v, w¯ ∈ Wi
, by definition. Since each Wi
is
a subspace, we then learn that for all a, b ∈ F,
av¯ + bw¯ ∈ Wi
,
and hence av¯ + bw¯ ∈ W. ¤
Thought question: Why is this never empty?
The union is a little trickier.
Proposition. W1 ∪ W2 is a subspace iff W1 ⊂ W2 or W2 ⊂ W1.
i hope this helped have a nice day/night :)
if 2 (3x - 4 ) =5, then x =
Answer:
2.167 (rounded to the nearest hundredths).
Step-by-step explanation:
Isolate the variable, x. Note the equal sign, what you do to one side, you do to the other. Do the opposite of PEMDAS.
PEMDAS is the order of operations, and stands for:
Parenthesis
Exponents (& Roots)
Multiplication
Division
Addition
Subtraction
~
First, divide 2 from both sides of the equation:
(2(3x - 4))/2 = (5)/2
3x - 4 = 2.5
Next, isolate the variable, x. Add 4 to both sides of the equation:
3x - 4 (+4) = 2.5 (+4)
3x = 2.5 + 4
3x = 6.5
Then, divide 3 from both sides of the equation:
(3x)/3 = (6.5)/3
x = 6.5/3 = 2.167 (rounded).
~
Answer:
We have this equation
2*(3x-4) = 5
We can start solving the parentheses
2*(3x- 4) = 5
6x - 8 = 5
We can add 8 to both sides
6x - 8 + 8 = 5 + 8
6x = 13
And divide by 6
6x/6 = 13/6
x = 13/6
Im asking a question because yes
+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
ANSWER WITH A, B, C, OR D.
A fruit stand has to decide what to charge for their produce. They need $10 for 4 apples and 4 oranges. They also need $12 for 6 apples and 6 oranges. We put this information into a system of linear equations.
Can we find a unique price for an apple and an orange?
Choose 1 answer:
A
Yes; they should charge $1.00 for an apple and $1.50 for an orange.
B
Yes; they should charge $1.00 for an apple and $1.00 for an orange.
C
No; the system has many solutions.
D
No; the system has no solution.
Answer:
I believe the answer would be A!
Step-by-step explanation:
If you need $10 total, then charging $1 for 4 apples would get you $4, and charging $1.50 for 4 oranges would get you $6, totaling $10!
Heeelp please!!! Picture included
Answer:
2nd choice
Step-by-step explanation:
A large bottle of water is leaking. The amount of ounces left in the bottle is shown in the function [tex]O(s) = 72-3s[/tex] is the amount of ounces left, and s is the number of seconds that is the water is leaking out. What is a reasonable domain and range for this function?
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Answer:
D: [0, 24]
R: [0, 72]
Step-by-step explanation:
The function only makes sense for non-negative values of time or water volume. The intercepts of the function are ...
y-intercept: 72
x-intercept: 72/3 = 24
so the reasonable domain is 0 ≤ s ≤ 24,
and the corresponding range is 0 ≤ O(x) ≤ 72.
The data represent the results for a test for a certain disease. Assume one individual from the group is randomly selected. Find the probability of getting someone who tests negative, given that he or she did not have the disease.
The individual actually had the disease
Yes No
Positive 135 11
Negative 99 145
Answer:
0.9295 = 92.95% probability of getting someone who tests negative, given that he or she did not have the disease.
Step-by-step explanation:
A probability is the number of desired outcomes divided by the number of total outcomes.
In this question:
11 + 145 = 156 people did not have the disease.
Out of those, 145 tested positive. So
[tex]p = \frac{145}{156} = 0.9295[/tex]
0.9295 = 92.95% probability of getting someone who tests negative, given that he or she did not have the disease.
So for this problem I got the scientific notation however I can not seem to figure out the standard notation. I thought it is the same answer but it is not. Can someone please help me out here please?
Answer:
567000000
Step-by-step explanation:
Standard is the actual number. Multiply 5.67 and 10^8.
Which point is the center of the circle?
w
Opoint w
O point X
o point Y
O point Z
Answer:
X o punto Y O punto z
Step-by-step explanation:
How many outcomes (sample points) for a deal of two cards from a 52-card deck are possible? Report your answer as an integer.
Answer:
1326
Step-by-step explanation:
[tex]{52\choose2}=\frac{52!}{(52-2)!2!}=\frac{52!}{50!*2!}=1326[/tex]
Complete this sentence: The longest side of a triangle is always opposite the
• A. angle with the smallest measure
O B. angle with the greatest measure
O C. shortest side
D. second-longest side
Answer:
B. angle with the greatest measure
opposite the largest angle
Please help me i will give brainlest please i need help
Answer:
Since you didn't mention which question.
Step-by-step explanation:
13.
[tex]1.\overline{52}\\[/tex] = 1.525252...
Let x = 1.525252...
10x = 15.2525252....
100x = 152.525252...
100x - x = 151.00
99x = 151
[tex]x = \frac{151}{99}\\\\or\\\\x = 1 \frac{52}{99}[/tex]
14.
4x + 10 = 8x - 26 [ corresponding angles are congruent ]
4x - 8x = - 26 - 10
- 4x = - 36
[tex]x = \frac{-36}{-4} \\\\x = 9[/tex]
15.
Given breadth of a rectangle is ( 2/3) its length.
Let the length be x
Therefore, breadth = ( 2 /3) of x
[tex]= \frac{2}{3} \times x\\\\=\frac{2}{3}x[/tex]
Given perimeter = 40m
Perimeter of a rectangle = 2( length + breadth)
[tex]40 = 2 (x + \frac{2}{3}x )\\\\\frac{40}{2} = \frac{2}{2}(x + \frac{2}{3}x)\\\\20 = x + \frac{2}{3}x\\\\20 = \frac{3x + 2x}{3}\\\\20 \times 3 = 5x \\\\x = \frac{60}{5}\\\\x = 12\\\\Therefore, Length = x = 12 \ m \ and \ breadth = \frac{2}{3}x = \frac{2}{3} \times 12 = 8 \ m[/tex]
16.
Sum of the angles of a triangle = 180°
Given ratio = 2 : 3 : 4
Sum of the ratio = 9
Therefore,
[tex]first \ angle = \frac{2}{9} \times 180 = 2 \times 20 = 40 ^\circ\\\\Second \ angle = \frac{3}{9} \times 180 = 3 \times 20 = 60^\circ\\\\Third angle = \frac{4}{9} \times 180 = 4 \times 20 = 80^\circ[/tex]
17.
Sum of interior angles of a polygon with n sides = ( n - 2) x 180°
Given polygon is pentagon, that is n = 5
Therefore, sum of the interior angles = ( 5 - 2) x 180 = 3 x 180 = 540°
That is ,
x + 125 + 125 + 88 + 60 = 540°
x + 398 = 540°
x = 540 - 398
x = 142°
Answer:
Please can you say which question?
Thank you
ABC ∆ where Angle A =90° , AB = 12 m, AC = 9 m . Find BC ?
( Show all your workings )
best answer will marked as brainalist
dont put fake ones
Answer:
15m
Step-by-step explanation:
Use Pythagoras
Folow the steps in the image
Answer:
:] brainlist me friends
A sociologist claims the probability that a person picked at random in Times Square in New York City is visiting the area is 0.83. You want to test to see if the claim is correct. State the null and alternative hypotheses.
Answer:
The answer is:
[tex]H_0: p=0.83\\\\H_a: p \neq 0.83[/tex]
Step-by-step explanation:
Now, we're going to test if sociologists claim to be have visited a region of 0.83 by a person picked randomly on Time In New York City.
Therefore, null or other hypotheses are:
[tex]H_0: p=0.83\\\\H_a: p \neq 0.83[/tex]
You have been doing research for your statistics class on the prevalence of severe binge drinking among teens. You have decided to use 2011 Monitoring the Future (MTF) data that have a scale (from 0 to 14) measuring the number of times teens drank 10 or more alcoholic beverages in a single sitting in the past 2 weeks.
a. According to 2011 MTF data, the average severe binge drinking score, for this sample of 914 teens, is 1.27, with a standard deviation of 0.80. Construct the 95% confidence interval for the true averse severe binge drinking score.
b. On of your classmates, who claims to be good at statistics, complains about your confidence interval calculation. She or he asserts that the severe binge drinking scores are not normally distributed, which in turn makes the confidence interval calculation meaningless. Assume that she or he is correct about the distribution of severe binge drinking scores. Does that imply that the calculation of a confidence interval is not appropriate? Why or why not?
Answer:
(1.218 ; 1.322)
the confidence interval is appropriate
Step-by-step explanation:
The confidence interval :
Mean ± margin of error
Sample mean = 1.27
Sample standard deviation, s = 0.80
Sample size, n = 914
Since we are using tbe sample standard deviation, we use the T table ;
Margin of Error = Tcritical * s/√n
Tcritical at 95% ; df = 914 - 1 = 913
Tcritical(0.05, 913) = 1.96
Margin of Error = 1.96 * 0.80/√914 = 0.05186
Mean ± margin of error
1.27 ± 0.05186
Lower boundary = 1.27 - 0.05186 = 1.218
Upper boundary = 1.27 + 0.05186 = 1.322
(1.218 ; 1.322)
According to the central limit theorem, sample means will approach a normal distribution as the sample size increases. Hence, the confidence interval is valid, the sample size of 914 gave a critical value at 0.05 which is only marginally different from that will obtained using a normal distribution table. Hence, the confidence interval is appropriate
