Answer:
2.665 < σ < 3.379
Step-by-step explanation:
Given :
s = 2.97
Sample size, n = 60
α = 80%
χ² Critical value (two - tailed), df = (60-1) = 59
χ² = 45.577 ; χ² = 73.279
The 80% confidence interval for the standard deviation :
s * √(n - 1) / χ² critical
2.97 * √(60 - 1) / 73.279 < σ < 2.97 * √(60 - 1) / 45.577
2.665 < σ < 3.379
A television camera is positioned 4000 ft from the base of a rocket launching pad. The angle of elevation of the camera has to change at the correct rate in order to keep the rocket in sight. Also, the mechanism for focusing the camera has to take into account the increasing distance from the camera to the rising rocket. Let's assume the rocket rises vertically and its speed is 800 ft/s when it has risen 3000 ft. (Round your answers to three decimal places.)
(a) How fast is the distance from the television camera to the rocket changing at that moment?
ft/s
(b) If the television camera is always kept aimed at the rocket, how fast is the camera's angle of elevation changing at that same moment?
rad/s
============================================
Explanation for part (a)
t = time in secondsx = horizontal distance from the camera to the launch pady = vertical distance from the launch pad to the rocket's locationz = distance from camera to the rocket at time tAll distances mentioned are in feet.
We'll have a right triangle which allows us to apply the pythagorean theorem. Refer to the diagram below.
a^2+b^2 = c^2
x^2+y^2 = z^2
Apply the derivative to both sides with respect to t. We'll use implicit differentiation and the chain rule.
[tex]x^2+y^2 = z^2\\\\\frac{d}{dt}[x^2+y^2] = \frac{d}{dt}[z^2]\\\\\frac{d}{dt}[x^2]+\frac{d}{dt}[y^2] = \frac{d}{dt}[z^2]\\\\2x*\frac{dx}{dt}+2y*\frac{dy}{dt}=2z*\frac{dz}{dt}\\\\x*\frac{dx}{dt}+y*\frac{dy}{dt}=z*\frac{dz}{dt}\\\\[/tex]
Now we'll plug in (x,y,z) = (4000,3000,5000). The x and y values are given. The z value is found by use of the pythagorean theorem. Ie, you solve 4000^2+3000^2 = z^2 to get z = 5000. Or you could note that this is a scaled copy of the 3-4-5 right triangle.
We know that dx/dt = 0 because the horizontal distance, the x distance, is not changing. The rocket is only changing in the y direction. Or you could say that the horizontal speed is zero.
The vertical speed is dy/dt = 800 ft/s and it's when y = 3000. It's likely that dy/dt isn't the same value through the rocket's journey; however, all we care about is the instant when y = 3000.
Let's plug all that in and isolate dz/dt
[tex]4000*0+3000*800=5000*\frac{dz}{dt}\\\\2,400,000=5000*\frac{dz}{dt}\\\\\frac{dz}{dt} = \frac{2,400,000}{5000}\\\\\frac{dz}{dt} = 480\\\\[/tex]
At the exact instant that the rocket is 3000 ft in the air, the distance between the camera and the rocket is changing by an instantaneous speed of 480 ft/s.
-----------------------------------------------------------------------
Explanation for part (b)
Again, refer to the diagram below.
We have theta (symbol [tex]\theta[/tex]) as the angle of elevation. As the rocket's height increases, so does the angle theta.
We can tie together the opposite side y with the adjacent side x with the tangent function of this angle.
[tex]\tan(\text{angle}) = \frac{\text{opposite}}{\text{adjacent}}\\\\\tan(\theta) = \frac{y}{x}[/tex]
Like before, we'll apply implicit differentiation. This time we'll use the quotient rule as well.
[tex]\tan(\theta) = \frac{y}{x}\\\\\frac{d}{dt}[\tan(\theta)] = \frac{d}{dt}\left[\frac{y}{x}\right]\\\\\sec^2(\theta)*\frac{d\theta}{dt} = \frac{\frac{dy}{dt}*x - y*\frac{dx}{dt}}{x^2}\\\\\sec^2(\theta)*\frac{d\theta}{dt} = \frac{800*4000 - 3000*0}{4000^2}\\\\\sec^2(\theta)*\frac{d\theta}{dt} = \frac{3,200,000}{16,000,000}\\\\\sec^2(\theta)*\frac{d\theta}{dt} = \frac{32}{160}\\\\\sec^2(\theta)*\frac{d\theta}{dt} = \frac{1}{5}\\\\[/tex]
Let's take a brief detour. We'll return to this later. Recall earlier that [tex]\tan(\theta) = \frac{y}{x}\\\\[/tex]
If we plug in y = 3000 and x = 4000, then we end up with [tex]\tan(\theta) = \frac{3}{4}\\\\[/tex] which becomes [tex]\tan^2(\theta) = \frac{9}{16}[/tex]
Apply this trig identity
[tex]\sec^2(\theta) = 1 + \tan^2(\theta)[/tex]
and you should end up with [tex]\sec^2(\theta) = 1+\frac{9}{16} = \frac{25}{16}[/tex]
So we can now return to the equation we want to solve
[tex]\sec^2(\theta)*\frac{d\theta}{dt} = \frac{1}{5}\\\\\frac{25}{16}*\frac{d\theta}{dt} = \frac{1}{5}\\\\\frac{d\theta}{dt} = \frac{1}{5}*\frac{16}{25}\\\\\frac{d\theta}{dt} = \frac{16}{125}\\\\\frac{d\theta}{dt} = 0.128\\\\[/tex]
This means that at the instant the rocket is 3000 ft in the air, the angle of elevation theta is increasing by 0.128 radians per second.
This is approximately 7.334 degrees per second.
The distance from the television camera to the rocket is changing at 480 ft/s while the camera's angle of elevation is changing at 0.128 rad/s
Let x represent the distance from the camera to the rocket and let h represent the height of the rocket.
a)
[tex]x^2=h^2+4000^2\\\\2x\frac{dx}{dt}=2h\frac{dh}{dt} \\\\x\frac{dx}{dt}=h\frac{dh}{dt} \\\\At \ h=3000\ ft, \frac{dh}{dt}=800\ ft/s;\\x^2=3000^{2} +4000^2\\x=5000\\\\\\x\frac{dx}{dt}=h\frac{dh}{dt} \\\\5000\frac{dx}{dt}=3000*800\\\\\frac{dx}{dt}=480\ ft/s[/tex]
b)
[tex]tan(\theta)=\frac{h}{4000} \\\\h=4000tan(\theta)\\\\\frac{dh}{dt}=4000sec^2(\theta)\frac{d\theta}{dt} \\\\\\At\ h=3000\ ft;\\\\tan\theta = \frac{3000}{4000}=\frac{3}{4} \\\\sec^2(\theta)=1+tan^2(\theta)=1+(\frac{3}{4})^2=\frac{25}{16} \\\\\\\frac{dh}{dt}=4000sec^2(\theta)\frac{d\theta}{dt}\\\\800=4000*\frac{25}{16}* \frac{d\theta}{dt}\\\\\frac{d\theta}{dt}=0.128\ rad/s[/tex]
Hence, The distance from the television camera to the rocket is changing at 480 ft/s while the camera's angle of elevation is changing at 0.128 rad/s
Find out more at: https://brainly.com/question/1306506
Please help and no links.While shopping, you find a shirt that you want. The shirt originally costs p dollars but it is on
sale for 20% off. Which of the following expressions could you use to find the price of the shirt
after the discount where p is the original price of the shirt? Select all that apply.
a) 0.2p
b) 0.8p
c) P-0.27
d) p-0.8p
(5.5 X10-6 + 6.3 X10-6)2
Answer:
2 • (59x10 - 60)
————————————————
5
Step-by-step explanation:
Find the least whole number N so that 123+N is a perfect square.
21
12^2 = 144
144 - 123 = 21
11^2 = 121
12^2 = 144
Between these
Answered by Gauthmath must click thanks and mark brainliest
Convert 2 1/3 into improper fraction: *
7/3
O 7/6
O 6/3
O 3/6
Answer:
7/3 is the answer
Step-by-step explanation:
-.p+p⎯.+p Simplify, please.
Answer:
34.5p-2.75
Step-by-step explanation:
First add -0.5p and 12p together which is 11.5p, then add 23p with 11.5p which is 34.5p And -2.75 remains the same
So the answer is 34.5p-2.75
Answer:
34.5p-2.75
Step-by-step explanation:
-0.5p+12p-2.75+23p=34.5p-2.75
A man purchased a magazine at the airport for $2.69. The tax on the purchase was $0.13. What is the tax rate at the airport? The tax rate is %. (Round to the nearest percent as needed.)
We need to find the percent, let's start but making the equation.
The price is 2.69
The tax cost is 0.13
So what percent of 2.69 is = 0.13.
Equation: X/100 x 2.69 = 0.13
Multiply each side by 100 so we can get x alone with the price: 2.69x = 13
Now to get x alone, we must divide both sides by 2.69: x = 4.8
Finally, we just round 4.8 to the nearest whole number, which is 5 (5 or above give it a shove, 4 or below let it go, we have 8 so we give it a shove). This means that the answer will be 5%.
I hope this helps! :)
A rocket is launched at t = 0 seconds. Its height, in meters above sea-level, is given by the equation
h = -4.9t2 + 112t + 395.
At what time does the rocket hit the ground? The rocket hits the ground after how many seconds
Answer:
Step-by-step explanation:
In order to find out how long it takes for the rocket to hit the ground, we only need set that position equation equal to 0 (that's how high something is off the ground when it is sitting ON the ground) and factor to solve for t:
[tex]0=-4.9t^2+112t+395[/tex]
Factor that however you are factoring in class to get
t = -3.1 seconds and t = 25.9 seconds.
Since time can NEVER be negative, it takes the rocket approximately 26 seconds to hit the ground.
Hello Abhinav the answer is ��cm^2
Answer:
i still se question marks
Step-by-step explanation:
Factorize (256⁴-1).
Use appropriate identity.
(256⁴-1)
= (256-1)⁴
Using identity (a-b)⁴ = a⁴−4a³b+6a²b²−4ab³+b⁴
Let a be 256 and b be 1
Then
256⁴−4(256)³(1)+6(256)²(1)²−4(256)(1)³+(1)⁴
After solving
(256²-1)²
(a-b)² = a²-2ab+b²
256²-2×256×1+1²
= (256²-1)(256²+1)
Must click thanks and mark brainliest
Answer:
Use identity:
a² - b² = (a + b)(a - b)Consider that:
256 = 2⁸Now factorize:
256⁴ - 1 = (2⁸)⁴ - 1 = 2³² - 1 = (2¹⁶ - 1)(2¹⁶ + 1) = (2⁸ - 1)(2⁸ + 1)(2¹⁶ + 1) = (2⁴ - 1)(2⁴ + 1)(2⁸ + 1)(2¹⁶ + 1) = (2² - 1)(2² + 1)(2⁴ + 1)(2⁸ + 1)(2¹⁶ + 1) = (2 - 1)(2 + 1)(2² + 1)(2⁴ + 1)(2⁸ + 1)(2¹⁶ + 1)Which statement is true about this quadratic equation?
y=x^(2)-11x+7
Answer: This quadratic equation has two real solutions.
Step-by-step explanation:
[tex]y=x^{2} -11x+7\\\\D=(-11)^{2} -4 \cdot 7=121-28=93 \: > 0\\\\x=\dfrac{11 \pm \sqrt{93} }{2}[/tex]
I need help guys thanks so much
I think its A) (f+g)(z)=|2x+4|-2
Step-by-step explanation:
Find the equation of the linear function represented by the table below in slope-intercept form.
Answer:
y=-4x-5
Step-by-step explanation:
The slope of the line is - 4, the equation of line is y=-4x-5
What is the sum of the geometric sequence 1, 3, 9, ... if there are 10 terms? (5 points)
Answer:
[tex]S_n = \frac{1 (1 - 3^{10})}{1 - 3} = 29524[/tex]
Step-by-step explanation:
There's a handy formula we can use to find the sum of a geometric sequence, and here it is
[tex]S_n = \frac{a_1 (1 - r^n)}{1 - r}[/tex]
The value n represents the amount of terms you want to sum in the sequence. The variable r is known as the common ratio, and a is just some constant. Let's find those values.
First lets visualize this sequence
[tex]n_1 = 1\\n_2 = 1 + 3\\n_3 = 1 + 3 + 3^2\\n_4=1+3+3^2+3^3\\...[/tex]
Okay so there's clearly a pattern here, let's write it a bit more concisely. For each n, starting at 1, we raise 3 to the (n-1) power, add it to what we had for the previous term.
[tex]S_n = \sum{3^{n-1}} = 3^{1 - 1} + 3^{2 - 1} + 3^{3-1} ...[/tex]
Our coefficients of r, and a, are already here! As you can see below, r is just 3, and a is just 1.
[tex]S_n = \sum{a*r^{n-1}}[/tex]
To finish up lets plug these coefficients in and get our sum after 10 terms.
[tex]S_n = \frac{1 (1 - 3^{10})}{1 - 3} = 29524[/tex]
D. Rom has just given an insurance company $35,000. In return, he will receive an annuity of $3,700 for 20 years. At what
rate of return must the insurance company invest this $35,000 in order to make the annual payments?
Answer:
0.53%
Step-by-step explanation:
hope it is well understood
The difference of a number and its opposite is 28. Find
the number.
Step-by-step explanation:
Lets break this word problem down:
"The difference" means we're going to be finding x - y ("difference" means we're finding how much one value "differs" from the other)
"a number and it's opposite" so we're doing x - y, where y = -x. So already, we can re-write this as x - (-x) or x + x
"is 28" so x + x = 28 ("is" always means "equals")
"Find the number" so we're finding x.
x - (-x) = 28 (I went back a step so I could write everything out more plainly)
simplify
x + x = 28
add
2x = 28
divide both sides by 2 to get x on its own
x = 14
Answer:
14
Which best describes the relationship between the line that passes through the points (6, -1) and (11, 2) and the line that passes through the
points (5-7) and (8-2)?
Answer:
D. Neither perpendicular nor parallel
Step-by-step explanation:
Let's find the slope (m) of both lines:
✔️Slope (m) of the line that passes through (6, -1) and (11, 2):
Slope (m) = change in y/change in x
Slope (m) = (2 -(-1))/(11 - 6) = 3/5
✔️Slope (m) of the line that passes through (5, -7) and (8, -2)
Slope (m) = change in y/change in x
Slope (m) = (-2 -(-7))/(8 - 5) = 5/3
✅The slope of both lines are not the same, therefore they are not parallel nor same line.
Also, the slope of one is not the negative reciprocal of the other, therefore they are not perpendicular.
I need you guy’s help answer thanks so much
Answer:
Yes 7i is the answer
Step-by-step explanation:
they are equivalent.
Find m∠F.
Find the answer to m∠F
Answer:
m∠F = 45°
Step-by-step explanation:
Notice the lengths of the given sides and the right angle. This is enough information to prove that this is a 45-45-90 triangle, or just basically a square cut diagonally.
Regardless if even just one side is given for a 45-45-90 triangle, all 45-45-90 triangles have one thing in common. The sides that form the right angle are equivalent and the hypotenuse is equal to one of the sides that form the right angle times the square root of two. I'm aware that it sounded confusing, as I'm awful at explaining, so just look at the picture I've attached instead of trying to understand my explanation that seemed like trying to learn a second language.
Look at the picture. See that FD = x times that square root of 2 and that DE = x. Now look back at your picture. It's connecting, now isn't it?
Now that we know that this is indeed a 45-45-90 triangle, we can confirm that m∠F = 45°
A contributor for the local newspaper is writing an article for the weekly fitness section. To prepare for the story, she conducts a study to compare the exercise habits of people who exercise in the morning to the exercise habits of people who work out in the afternoon or evening. She selects three different health centers from which to draw her samples. The 57 people she sampled who work out in the morning have a mean of 5.2 hours of exercise each week. The 70 people surveyed who exercise in the afternoon or evening have a mean of 4.5 hours of exercise each week. Assume that the weekly exercise times have a population standard deviation of 0.6 hours for people who exercise in the morning and 0.4 hours for people who exercise in the afternoon or evening. Let Population 1 be people who exercise in the morning and Population 2 be people who exercise in the afternoon or evening.
Step 1 of 2: Construct a 95% confidence interval for the true difference between the mean amounts of time spent exercising each week by people who work out in the morning and those who work out in the afternoon or evening at the three health centers. Round the endpoints of the interval to one decimal place, if necessary.
Answer:
The 95% confidence interval for the true difference between the mean amounts of time spent exercising each week by people who work out in the morning and those who work out in the afternoon or evening at the three health centers is (0.5, 0.9).
Step-by-step explanation:
Before building the confidence intervals, we need to understand the central limit theorem and subtraction of normal variables.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
Subtraction between normal variables:
When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.
In the morning:
Sample of 57, mean of 5.2, standard deviation of 0.6, so:
[tex]\mu_1 = 5.2[/tex]
[tex]s_1 = \frac{0.6}{\sqrt{57}} = 0.0795[/tex]
In the afternoon/evening:
Sample of 70, mean of 4.5, standard deviation of 0.4, so:
[tex]\mu_2 = 4.5[/tex]
[tex]s_2 = \frac{0.2}{\sqrt{70}} = 0.0239[/tex]
Distribution of the difference:
[tex]\mu = \mu_1 - \mu_2 = 5.2 - 4.5 = 0.7[/tex]
[tex]s = \sqrt{s_1^2+s_2^2} = \sqrt{0.0795^2 + 0.0239^2} = 0.083[/tex]
Confidence interval:
The confidence interval is:
[tex]\mu \pm zs[/tex]
In which
z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].
95% confidence level
So [tex]\alpha = 0.05[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.05}{2} = 0.975[/tex], so [tex]Z = 1.96[/tex].
The lower bound of the interval is:
[tex]\mu - zs = 0.7 - 1.96*0.083 = 0.5[/tex]
The upper bound of the interval is:
[tex]\mu + zs = 0.7 + 1.96*0.083 = 0.9[/tex]
The 95% confidence interval for the true difference between the mean amounts of time spent exercising each week by people who work out in the morning and those who work out in the afternoon or evening at the three health centers is (0.5, 0.9).
Three children have some marbles.
Shireen has m marbles.
Nazaneen has three times as many marbles as Shireen.
Karly has 4 more marbles than Shireen.
(a) Write down an expression, in terms of m, for
(i) the number of marbles Nazaneen has,
Here we want to create algebraic expressions for different quantities.
i) Nazaneen has 3*m marbles.
ii) Karly has m + 4 marbles.
a) The given data is:
Shireen has m marbles.
Nazaneen has three times as many marbles as Shireen.
Knowing that Shireen has m marbles, we can conclude that Nazaneen has:
3*m marbles.
Karly has 4 more marbles than Shireen, then Karly has m + 4 marbles.
Then the equations for the number of marbles that each one has are:
Shireen = m
i) Nazaneen has 3*m marbles.
ii) Karly has m + 4 marbles.
If you want to learn more, you can read:
https://brainly.com/question/24327241
the value of 5/121^1/2
Answer:
√5/121
Step-by-step explanation:
formula: a^½=√a
(⁵/¹²¹)^½=√⁵/¹²¹
Does the graph represent a function and if so, why?
A) Yes, there is more than one ordered pair in this list.
B) Yes, no two sets of ordered pairs occupy the same location.
C) No, some of the ordered pairs in this list have the same second element.
D) No, some of the ordered pair in this graph have the same first element.
Answer:
D
Step-by-step explanation:
if you draw any vertical line through a function it should have a max of one intersection point so if the graph, reading from left to right doubles back on itself, it is not a function
If the function y=x^5 is transformed to y=x^5+3 what’s the statement
I dont know what you mean by the question but according to me.
If y=x^5
y=x^5+3
Then y+3=x^5+3
Answered by Gauthmath must click thanks and mark brainliest
Can you provide a solution or a formula?
144 x 1.25 = 180
Answer: 144
Answer:
144
Step-by-step explanation:
144 × 1.25 = 180
We add the 1 to .25 to represent the original value plus the 25% increase.
Or you could have divided 180 by 1.25 to find original price.
I need help on this problem
9514 1404 393
Answer:
see attached
Step-by-step explanation:
(a) The graph is scaled by a factor of 2, and shifted up 1 unit. The scaling moves each point away from the x-axis by a factor of 2. The points on the x-axis stay there. The translation moves that scaled figure up 1 unit.
__
(b) The graph is reflected across the x-axis and shifted right 4 units. The point on the x-axis stays on the x-axis.
This answer was confusing for sure
Answer: lol ez
B.
Step-by-step explanation: XD
Answer:
D
Step-by-step explanation:
The general formula for the sine or cosine function is
y = A*Sin(Bx + C) + D
C = 0 in this case
B = pi / 3
The period is given by the formula
P = 2 * pi / B
P = 2 * pi//pi/3
The 2 pis cancel and you are left with 2*3 = 6
How to solve following question?
In an upcoming election, 15% of married voters will vote for Candidate A, while the rest will vote for Candidate B; 80% of unmarried voters will vote for Candidate A, while the rest will vote for Candidate B. Which of the following represents the lowest percentage from all voters combined (married and unmarried) that must be unmarried (not married) in order for Candidate A to win the election?
Answer:
The lowest percentage from all voters combined that must be unmarried in order for Candidate A to win the election is 53.85%.
Step-by-step explanation:
Proportion married:
x are married
1 - x are unmarried.
Will vote for candidate A:
15% of x
80% of 1 - x. So
[tex]0.15x + 0.8(1-x)[/tex]
Candidate A wins:
If his proportion is more than 50%, that is:
[tex]0.15x + 0.8(1-x) > 0.5[/tex]
[tex]0.15x+ 0.8 - 0.8x > 0.5[/tex]
[tex]-0.65x > -0.3[/tex]
[tex]0.65x < 0.3[/tex]
[tex]x < \frac{0.3}{0.65}[/tex]
[tex]x < 0.4615[/tex]
Highest percentage of married is 46.15%, so:
The lowest percentage of unmarried is:
100 - 46.15 = 53.85%.
The lowest percentage from all voters combined that must be unmarried in order for Candidate A to win the election is 53.85%.
To collect data on the signal strengths in a neighborhood, Briana must drive from house to house and take readings. She has a graduate student, Henry, to assist her. Briana figures it would take her 12 hours to complete the task working alone, and that it would take Henry 18 hours if he completed the task by himself. How long will it take Briana and Henry to complete the task together?
a. 6.7 hours
b. 7.2 hours
c. 5.6 hours
Answer:
The correct answer is B. It will take them 7.2 hours.
Step-by-step explanation:
Given that to collect data on the signal strengths in a neighborhood, Briana must drive from house to house and take readings, and she has a graduate student, Henry, to assist her, and Briana figures it would take her 12 hours to complete the task working alone, and that it would take Henry 18 hours if he completed the task by himself, to determine how long will it take Briana and Henry to complete the task together the following calculation must be performed:
1/12 + 1/18 = X
18 / (12 x 18) + 12 / (18 x 12) = X
30/216 = X
5/36 = X
36/5 = 7.2
Therefore, they will be able to finish the task in 7.2 hours.
true or false?
help me please
Answer:
False
Step-by-step explanation:
The point that is equidistant from the vertices of a triangle is called the circumcenter.
9514 1404 393
Answer:
False
Step-by-step explanation:
The incenter is the center of the inscribed circle, which is tangent to all of the sides of the triangle. The incenter is equidistant from the sides, not the vertices.
_____
Additional comment
The circumcenter is the center of the circumscribing circle. Each of the vertices of the triangle is on the circumcircle, so the circumcenter is equidistant from the vertices.
The incenter is located at the intersection point of the angle bisectors. The circumcenter is located at the intersection point of the perpendicular bisectors of the sides.
