Answer:
a. 0.302 dB/s
b. 2.34 dB/s
c. 1.24 dB/s
Step-by-step explanation:
a) Find the rate of change of the sound pressure P with respect to time if W=7.2 and dW/dt = 0.5 at some given time t.
Since P = 10log(W/W₀), its rate of change with respect to time is
dP/dt = dP/dW × dW/dt
dP/dW = d[10logW - 10logW₀]/dt
dP/dW = d[10lnW/2.303 - 10logW₀]/dt
= 10/2.303W - 0
= 10/(2.303W)
dP/dt = dP/dW × dW/dt
dP/dt = 10/(2.303W) × dW/dt
Since dW/dt = 0.5 when W = 7.2, then
dP/dt = 10/(2.303 × 7.2) × 0.5
dP/dt = 10/16.5816 × 0.5
dP/dt = 0.603 × 0.5
dP/dt = 0.302 dB/s
b) If the variable sound power W is given by W = t² + t + 1, find the rate of change of the sound pressure P, at time t = 3s.
Since P = 10log(W/W₀), its rate of change with respect to time is
dP/dt = dP/dW × dW/dt
dP/dW = d[10logW - 10logW₀]/dt
dP/dW = d[10lnW/2.303 - 10logW₀]/dt
= 10/2.303W - 0
= 10/(2.303W)
and dW/dt = d(t² + t + 1)/dt = 2t + 1
So, dP/dt = dP/dW × dW/dt
dP/dt = 10/(2.303W) × (2t + 1)
dP/dt = 10(2t + 1)/(2.303W)
dP/dt = 10(2t + 1)/[2.303(t² + t + 1)]
we then substitute t = 3 into the equation
dP/dt = 10(2t + 1)/[2.303(t² + t + 1)]
dP/dt = 10(2(3) + 1)/[2.303((3)² + 3 + 1)]
dP/dt = 10(6 + 1)/[2.303(9 + 3 + 1)]
dP/dt = 10(7)/[2.303(13)]
dP/dt = 70/29.939
dP/dt = 2.34 dB/s
c) If W = cos 0.2t, find the rate of change of the sound pressure P, at time t = 15 (calculators in radians)
Since dP/dt = dP/dW × dW/dt and dP/dW = 10/(2.303W) and W = cos(0.2t), dW/dt = -0.2sin(0.2t)
So, dP/dt = dP/dW × dW/dt
dP/dt = 10/(2.303W) × -0.2sin(0.2t)
dP/dt = -20sin(0.2t)/(2.303W)
dP/dt = -20sin(0.2t)/(2.303cos(0.2t))
dP/dt = -20tan(0.2t)/2.303
when t = 15, we have
dP/dt = -20tan(0.2 × 15)/2.303
dP/dt = -20tan3/2.303
dP/dt = -20 × -0.1425/2.303
dP/dt = 2.8509/2.303
dP/dt = 1.238
dP/dt ≅ 1.24 dB/s
Help, please! With workings too!
I'm thinking of a 3-digit number.
When it is divided by 9, the remainder is 3
When it is divided by 2, the remainder is 1
When it is divided by 5, the remainder is 4
What is my number?
3-digit number is abc. ( just call it)
abc= 9d + 3, meaning abc = 3e
abc = 2k + 1, meaning abc is an odd number
abc = 5t + 4, meaning c = 9 ( because abc is an odd number so c can not be 4)
so a+b must be equal 3.
abc can be 309, 219, 129
A researcher wants to investigate the effects of environmental factors on IQ scores. For an initial study, she takes a sample of 400 people who grew up as the only child. She finds that 48.5% of them have an IQ score over 100. It is known that 50% of the general population has an IQ score exceeding 100.(a) Find the mean of p, where p is the proportion of people with IQ scores over 100 in a random sample of 400 people.(b) Find the standard deviation of p.(c) Compute an approximation for P(p is greater than or equal to 0.485), which is the probability that there will be 48.5% or more individuals with IQ scores over 100 in a random sample of 400. Round answer to 4 decimal places.
Answer:
a) p = 0.5.
b) s = 0.025.
c) 0.7257 = 72.57% probability that there will be 48.5% or more individuals with IQ scores over 100 in a random sample of 400.
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
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.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]
It is known that 50% of the general population has an IQ score exceeding 100. Sample of 400.
This means that [tex]n = 400, p = 0.5, s = \sqrt{\frac{0.5*0.5}{400}} = 0.025[/tex]
(a) Find the mean of p, where p is the proportion of people with IQ scores over 100 in a random sample of 400 people
By the Central Limit Theorem, p = 0.5.
(b) Find the standard deviation of p.
By the Central Limit Theorem, s = 0.025.
(c) Compute an approximation for P(p is greater than or equal to 0.485), which is the probability that there will be 48.5% or more individuals with IQ scores over 100 in a random sample of 400.
This is 1 subtracted by the p-value of Z when X = 0.485. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{0.485 - 0.5}{0.025}[/tex]
[tex]Z = -0.6[/tex]
[tex]Z = -0.6[/tex] has a p-value of 0.2743.
1 - 0.2743 = 0.7257.
0.7257 = 72.57% probability that there will be 48.5% or more individuals with IQ scores over 100 in a random sample of 400.
Helpppplpppp
Which choice is equivalent to the product below?
Answer:
6
Step-by-step explanation:
=>root(2) x root(3) x root(6)
=>root(2x3) x root(6)
=>root(6) x root(6)
=>6
Consider the following sample data: x 12 18 20 22 25 y 15 20 25 22 27 Click here for the Excel Data File a. Calculate the covariance between the variables. (Round your intermediate calculations to 4 decimal places and final answer to 2 decimal places.)
Answer:
The covariance between the variables is 21.10 and the Correlation coefficient is 0.9285.
Step-by-step explanation:
Hence,
what does the equation inverse of the function found in part b represent in the contract of the problem ? explain your answer .
context to question - At a carnaval , you pay $15 for admission plus $3 for each ride that you go on .
Answer:
[tex]f^{-1}(x) =\frac{x}{3} - 5[/tex]
The inverse function is to calculate the number of rides; given the amount paid
Step-by-step explanation:
Given
[tex]Admission = 15[/tex]
[tex]Ride = 3[/tex] per ride
Required
Explain the inverse function
First, we calculate the function
Let x represents the number of rides
So:
[tex]f(x) = Admission + Ride * x[/tex]
[tex]f(x) = 15 + 3 * x[/tex]
[tex]f(x) = 15 + 3x[/tex]
For the inverse function, we have:
[tex]y = 15 + 3x[/tex]
Swap x and y
[tex]x = 15 + 3y[/tex]
Make 3y the subject
[tex]3y = x - 15[/tex]
Make y the subject
[tex]y =\frac{x}{3} - 5[/tex]
Replace y with the inverse function
[tex]f^{-1}(x) =\frac{x}{3} - 5[/tex]
The above is to calculate the number of rides; given the amount paid
[(4 x 2) + (2 x 3)] ÷ 2 x 5 =
Answer:
1.4
Step-by-step explanation:
= [(4 x 2) + (2 x 3)] ÷ 2 x 5
= [8 + 6] / 10
= 14 / 10
= 1.4
1.3.33 Question Help A certain triangle has a perimeter of 3078 mi. The shortest side measures 71 mi less than the middle side, and the longest side measures 371 mi more than the middle side. Find the lengths of the three sides. The shortest side is mi long.
Answer:
the shortest side is 855 miles long.
Step-by-step explanation:
a + b + c = 3078 miles
a = b - 71
c = b + 371
=>
(b-71) + b + (b+371) = 3078
3b + 300 = 3078
3b = 2778
b = 926 miles
a = 926 - 71 = 855 miles
c = 926 + 371 = 1297 miles
identify the 3D shape :)thank you
If you folded the figure up, you would have a prism where the parallel bases are right triangles. Each lateral face is a rectangle.
It might help to imagine a room where the floor and ceiling are triangles (they are identical or congruent triangles). Each wall of this room is one of the rectangles shown.
The state lottery board is examining the machine that randomly picks the lottery numbers. On each trial, the machine outputs a ball with one of the digits 0 through 9 on it. (The ball is then replaced in the machine.) The lottery board tested the machine for 1000 trials and got the following results:
Outcome 0 1 2 3 4 5 6 7 8 9
Number of Trials 4 2 5 3 2 6 6 3 6 3
Required:
a. From these results, compute the experimental probability of getting an odd number.
b. Assuming that the machine is fair, compute the theoretical probability of getting an odd number.
Answer:
0.425
0.5
Step-by-step explanation:
Given :
Outcome 0 1 2 3 4 5 6 7 8 9
Number of Trials 4 2 5 3 2 6 6 3 6 3
The experimental probability of obtaining an odd number :
Odd outcomes are : 1, 3, 5, 7, 9
Total number of trials = Σ(4 2 5 3 2 6 6 3 6 3) = 40
Total number of odd outcomes = (2+3+6+3+3) = 17
Experimental probability = number of prefferwd outcomes / total number of trials
Experimental P(odd). = 17 / 40 = 0.425
The theoretical probability of getting an odd number :
Required outcome / Total possible outcomes
Number of odd values / total number of values
5 / 10 = 1/2
Answer:
0.510
0.500
Step-by-step explanation:
part c) = A
name me brainiest
On a given test with a maximum possible score of 100 points, the vast majority of the 259 students in a class scored either a perfect score or a zero, with only one student scoring within 10 points of the mean. Could we say that the test scores are normally distributed? Explain your answer.
Answer:
no, in a normal distribution mode=median=mean. So while in theory, the median and the mean can be the same, the mode is not.
Step-by-step explanation:
Based on the maximum possible score, the scores by the student, and the deviation, we cannot say that the test scores are normally distributed.
What makes a distribution normal?In a normal distribution, the mean, mode and median have to be equal thanks to the bell-shaped nature of the distribution.
In this case, the median will be the score of the single student who is 10 points off the mean.
The mean will be affected by the extreme values of zero and a perfect score, and the mode will either be zero or 100.
The mean, mode, and median are therefore not the same so this isn't a normal distribution.
Find out more on normal distributions at https://brainly.com/question/23418254.
#SPJ9
PlEaSe HelP mEakwhtb4qhnga
Answer:
d. y = x + 6
Step-by-step explanation:
Equation of AD can be written in the slope-intercept form, y = mx + b
First, find the slope (m) and y-intercept (b) of line AD.
✔️Slope (m) = change in y/change in x
Using two points on line AD, (-5, 1) and (0, 6):
Slope (m) = (6 - 1)/(0 - (-5))
Slope (m) = 5/5
m = 1
✔️y-intercept (b) is the point where the line cuts across the y-axis = 6
b = 6
✔️To write the equation, substitute m = 1 and b = 6 into y = mx + b
y = 1(x) + 6
y = x + 6
Use the graph or table to identify the value that makes this relationship proportional.
Answer:
33
Step-by-step explanation:
Pls vote my answer as brainliest
Answer:
33
Step-by-step explanation:
Do the following lengths form a right triangle?
Answer:
yes, this forms a right angle
A bin of 50 manufactured parts contains 3 defective parts and 47 non-defective parts. A sample of size 6 parts is selected from 50 parts. Selected parts are not replaced. How many different samples are there of size six that contain exactly 2 defective parts? What is the probability that a sample contains exactly 2 defective parts?
Answer:
535,095 different samples of size six that contain exactly 2 defective parts.
0.0337 = 3.37% probability that a sample contains exactly 2 defective parts.
Step-by-step explanation:
A probability is the number of desired outcomes divided by the number of total outcomes.
As the order of the parts is not important, the combinations formula is used to solve this question.
Combinations formula:
[tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
How many different samples are there of size six that contain exactly 2 defective parts?
2 defective from a set of 3, and 4 non-defective from a set of 47. So
[tex]D = C_{3,2}*C_{47,4} = \frac{3!}{2!1!}*\frac{47!}{4!43!} = 535095[/tex]
535,095 different samples of size six that contain exactly 2 defective parts.
What is the probability that a sample contains exactly 2 defective parts?
The total number of samples is:
[tex]T = C_{50,6} = \frac{50!}{6!44!} = 15890700[/tex]
Then...
[tex]p = \frac{D}{T} = \frac{535095}{15890700} = 0.0337[/tex]
0.0337 = 3.37% probability that a sample contains exactly 2 defective parts.
Solve for X in the triangle. Round your answer to the nearest TENTH. (LISTING BRAINLIST PLZ HELP)
Answer:
2.3 =x
Step-by-step explanation:
We know the opposite and adjacent sides.
Since this is a right triangle, we can use trig functions
tan 38 = opp/ adj
tan 38 = x/3
3 tan 38 = x
2.34385688= x
To the nearest tenth
2.3 =x
Answer:
x ≈ 3.9
General Formulas and Concepts:
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightEquality Properties
Multiplication Property of Equality Division Property of Equality Addition Property of Equality Subtraction Property of EqualityTrigonometry
[Right Triangles Only] SOHCAHTOA [Right Triangles Only] tanθ = opposite over adjacentStep-by-step explanation:
Step 1: Define
Identify variables
Angle θ = 38°
Opposite Leg = x
Adjacent Leg = 5
Step 2: Solve for x
Substitute in variables [tangent]: tan38° = x/5[Multiplication Property of Equality] Multiply 5 on both sides: 5tan38° = xRewrite: x = 5tan38°Evaluate: x = 3.90643Round: x ≈ 3.9RJM Enterprises is a manufacturer of consumer electronics products. The industry is very competitive, and RJM has seen its profits fall in recent years, including an operating loss of $16,328 last year. RJM was able to turn that around this year by aggressively cutting costs. The summarized financial results for RJM are shown below:
Answer: hello your question has some missing data attached below is the missing data
answer :
∑ Volume variance = $55272
∑ Sales price variance = $41944 ( F )
Step-by-step explanation:
First step : prepare a flexible budget data for the current year using the formulae below
flexible budget = Actual units * Budgeted rate
and
Sales price variance = Actual - Budgeted data
Attached below is the Table showing the evaluation of sales price variance and volume variance
If a rectangular prism has a length of 3 1/2 in and a width of 9 in and a height of 3 1/2, what would the surface area be?
The surface area is 150.5 in
Answer:
The surface area of this rectangular prism is 150.5 [tex]inches^{2}[/tex].
Step-by-step explanation:
The formula for finding the surface area of a rectangular prism is this :
A=2(wl + hl + hw)
l = 3.5, w = 9, h = 3.5
Now we substitute those values in and solve for A.
A = 2 · ( 9 · 3.5 + 3.5 · 3.5 + 3.5 ·9) = 150.5
The surface area of this rectangular prism is 150.5 [tex]inches^{2}[/tex].
Hope this helps, please mark brainliest. Have a great day!
Which is more economical: purchasing the economy size of a detergent at 3 kilograms for $3.15 or purchasing the regular size at 720 grams for 60c?
Answer:
Due to the lower price per kilogram, purchasing the regular size at 720 grams for 60c is more economical.
Step-by-step explanation:
Which is more economical?
Whichever situation has the lowest price per kilogram.
3 kilograms for $3.15
3.15/3 = $1.05 per kilogram.
720 grams for 60c
0.6/0.72 = $0.83 per kilogram.
Due to the lower price per kilogram, purchasing the regular size at 720 grams for 60c is more economical.
The quotient of 36 and 9 multiplied by 7
Answer:
6
Step-by-step explanation:
6*9 = 54
6*6 = 36
6*7 = 42
Find the equation of the circle that has a diameter with endpoints located at (-3,6) and (9,6).
Answer:
C
Step-by-step explanation:
Diameter is 12.
Radius is 6
Center is (3,6)
Use the formula for simple interest, I = Prt, to find the indicated quantity. Assume a 360 day year.
1 = $24; P = $1200; t = 90 days; r = ?
r=% (Simplify your answer.)
Answer:
r = 8%
Step-by-step explanation:
Given that,
Interest, I = $24
Principal, P = $1200
Time, t = 90 days = 90/360 = 1/4 years
We need to find the rate.
We know that,
The simple interest is given by :
[tex]I=\dfrac{Prt}{100}[/tex]
Put all the values,
[tex]r=\dfrac{100I}{Pt}\\\\r=\dfrac{100\times 24}{1200\times \dfrac{1}{4}}\\\\r=8\%[/tex]
So, the rate is 8%.
Which relations represent functions?
Input
Output
3
5
-b
9
d
Input
Output
7
-3
y
5
Input
Output
John
52
5'1 in height plus 7 cm how tall am I ?
Answer:
5.313 ft (about 5'3.75")
If 10 miles is 70% of the distance,
what is the total distance?
a. Chéo hóa ma trận A .
b. Từ kết quả câu a, hãy tính 10 A .
Given that the length of the figure below is x + 2, its width is
2- 2, and its perimeter is 24, solve for 2.
Answer:
hear is your answer in attachment please give me some thanks
Find the critical value ta/2 needed to construct a confidence interval of the given level with the given sample size. Round the answers to three decimal places.
(a) For level 90% and sample size 8.
(b) For level 99% and sample size 11.
(c) For level 95% and sample size 25.
(d) For level 99.5% and sample size 10.
Answer:
1.894
3.169
2.064
3.690
Step-by-step explanation:
A.) 90% ; sample size = 8
Degree of freedom, df = n - 1
t(1 - α/2, 7) = t0.05, 7 = 1.894
B.) 99% ; sample size = 11
Degree of freedom, df = n - 1
t(1 - α/2, 10) = t0.005, 10 = 3.169
C.) 95% ; sample size = 25
Degree of freedom, df = n - 1
t(1 - α/2, 24) = t0.025,24 = 2.064
(D.) 99.5% and sample size 10.
Degree of freedom, df = n - 1
t(1 - α/2, 9) = t0.0025,9 = 3.690
find this solution for mathematical quiz
Answer:
[tex]-\sqrt{2} + \sqrt{2}i[/tex]
Step-by-step explanation:
Angle of 9pi/4
The equivalent angle of [tex]\frac{9\pi}{4}[/tex], on the first lap, is found subtracting this angle from [tex]2\pi[/tex]. Thus:
[tex]\frac{9\pi}{4} - 2\pi = \frac{9\pi}{4} - \frac{8\pi}{4} = \frac{\pi}{4}[/tex]
Thus, the sine and cosine are:
[tex]\sin{(\frac{9\pi}{4})} = \sin{(\frac{\pi}{4})} = \frac{\sqrt{2}}{2}[/tex]
[tex]\cos{(\frac{9\pi}{4})} = \cos{(\frac{\pi}{4})} = \frac{\sqrt{2}}{2}[/tex]
Angle of 3pi/2
On the first lap of the circle, thus no need to find the equivalent angle. We have that:
[tex]\sin{(\frac{3\pi}{2})} = -1, \cos{(\frac{3\pi}{2})} = 0[/tex]
Expression:
[tex]4(\cos{(\frac{9\pi}{4})} + i\sin{(\frac{9\pi}{4})}) \div 2(\cos{(\frac{3\pi}{2})} + i\sin{(\frac{3\pi}{2})})[/tex]
[tex]4(\frac{\sqrt{2}}{2} + i\frac{\sqrt{2}}{2}) \div 2(0 - i)[/tex]
[tex]\frac{2\sqrt{2} + 2\sqrt{2}i}{-2i} \times \frac{i}{i}[/tex]
Considering that [tex]i^2 = -1[/tex]
[tex]\frac{-2\sqrt{2}+2\sqrt{2}i}{2}[/tex]
[tex]-\sqrt{2} + \sqrt{2}i[/tex]
What is the value of x for x +20 x=22
Answer:
x(1+20)=22
21x=22
x= 22/21
x= 1.05
Step-by-step explanation:
Answer:
2!!!
Step-by-step explanation:
the person is wrong.. 2+20=22
Work out the following, giving your answers in their simplest form:
b) 5/9 ÷ 5
Answer:
5/9÷55/9×1/51/9Hope it helps youAnswer:
Since i m not sure of the equation i have dont both possible ways :)
Step-by-step explanation:
b)
(5/9) ÷ 5
[tex]= \frac{5}{9} \div 5\\\\=\frac{\frac{5}{9}}{5}\\\\=\frac{5}{9 \times 5}\\\\=\frac{1}{9}[/tex]
5/(9÷5)
[tex]=\frac{5}{9 \div5}\\\\= \frac{5}{\frac{9}{5}}\\\\=\frac{5 \times 5}{9}\\\\=\frac{25}{9}[/tex]