Answer:
yes.
Step-by-step explanation:
Ratios are proportional if they represent the same relationship. One way to see if two ratios are proportional is to write them as fractions and then reduce them. If the reduced fractions are the same, your ratios are proportional.
6/9 divided by 3/3= 2/3
proportional
Write all your steps leading to the answers.) X and Y have joint density function f_(XY)(x,y)=B(1+xy), |x|<1,|y|l; zero, otherwise.
(1) Find B so that f_(XY) (x,y) is a valid joint density function.
(2) Prove or disprove X, Y are uncorrected.
(3) Prove or disprove X, Y are independent.
(4) Prove or disprove X^2 and Y^2 are independent.
(1) To find the value of B that makes f_(XY)(x,y) a valid joint density function, we need to ensure that the total probability over the entire domain is equal to 1. In this case, the domain is |x|<1 and |y|<1.
The integral of f_(XY)(x,y) over the given domain should be equal to 1:
∫∫ f_(XY)(x,y) dx dy = 1
∫∫ B(1+xy) dx dy = 1
To solve this integral, we integrate with respect to x first and then with respect to y:
∫(∫ B(1+xy) dx) dy
∫[Bx + B(xy^2)/2] dy, integrating with respect to x
Bxy + B(xy^2)/2 + C, integrating with respect to y
Now, evaluate the integral over the given domain:
∫[-1,1] [Bxy + B(xy^2)/2 + C] dy
[Bxy^2/2 + B(xy^3)/6 + Cy] evaluated from -1 to 1
[B/2 + B/6 + C] - [-B/2 - B/6 - C]
(B/2 + B/6 + C) - (-B/2 - B/6 - C)
2B/3 = 1
Solving for B:
B = 3/2
Therefore, the value of B that makes f_(XY)(x,y) a valid joint density function is B = 3/2.
(2) To determine if X and Y are uncorrelated, we need to calculate the covariance between X and Y. If the covariance is zero, then X and Y are uncorrelated.
Cov(X, Y) = E[XY] - E[X]E[Y]
To calculate E[XY], we need to find the joint expectation:
E[XY] = ∫∫ xy f_(XY)(x,y) dx dy
E[XY] = ∫∫ xy (3/2)(1+xy) dx dy
Integrating over the domain |x|<1 and |y|<1, we can calculate E[XY].
Similarly, we need to calculate E[X] and E[Y] to determine Cov(X, Y).
If Cov(X, Y) is found to be zero, then X and Y are uncorrelated.
(3) To prove or disprove independence between X and Y, we need to check if the joint probability density function (pdf) can be factorized into the product of the marginal pdfs of X and Y.
If f_(XY)(x,y) = f_X(x)f_Y(y), then X and Y are independent.
To determine if this factorization holds, we need to compare the joint pdf f_(XY)(x,y) with the product of the marginal pdfs f_X(x) and f_Y(y). If they are equal, then X and Y are independent. Otherwise, they are dependent.
(4) To prove or disprove the independence between X^2 and Y^2, we follow a similar approach as in (3). We compare the joint pdf of X^2 and Y^2 with the product of their marginal pdfs. If they are equal, X^2 and Y^2 are independent. Otherwise, they are dependent.
By examining the factorization of the joint pdfs and comparing them with the product of the marginal pdfs, we can determine the independence relationships between the variables X, Y, X^2, and Y^2.
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Find the midpoint of the segment with the following endpoints.
(9,6) and (5,2)
Answer:
[tex]M(7 ; 4)[/tex]
Step-by-step explanation:
midpoint -M
[tex]M(\frac{x_{1}+x_{2}}{2} ; \frac{y_{1}+y_{2}}{2} )[/tex]
[tex]M(\frac{9+5}{2} ; \frac{6+2}{2} )[/tex]
[tex]M(7 ; 4)[/tex]
Answer:
(7, 4 )
Step-by-step explanation:
Given endpoints (x₁, y₁ ) and (x₂, y₂ ) then the midpoint is
( [tex]\frac{x_{1}+x_{2} }{2}[/tex] , [tex]\frac{y_{1}+y_{2} }{2}[/tex] )
Here (x₁, y₁ ) = (9, 6) and (x₂, y₂ ) = (5, 2) , then
midpoint = ( [tex]\frac{9+5}{2}[/tex] , [tex]\frac{6+2}{2}[/tex] ) = ([tex]\frac{14}{2}[/tex] , [tex]\frac{8}{2}[/tex] ) = (7, 4 )
PLSS HELP IMMEDIATELY!!! i’ll give brainiest if u don’t leave a link!
Answer:
it's arm will regenerate and grow back
plz mark me as brainliest
Answer:
B. The arm will regenterate
f (x) = -3x + 1
g(x) = x2 + 2x – 5
Find g (f (x))
Answer: f
= x = − 3 x + 1 = x = 1 4 g = x 2 + 2 x − 5f( x ) = f ( x )
Step-by-step explanation:
A teacher would like to estimate the mean number of steps students take during the school day. To do so, she selects a random sample of 50 students and gives each one a pedometer at the beginning of the school day. They wear the pedometers all day and then return them to her at the end of the school day. From this, she computes the 98% confidence interval for the true mean number of steps students take during the school day to be 8,500 to 10,200. If the teacher had used a 90% confidence interval rather than a 98% confidence interval, what would happen to the width of the interval?
It would increase by 8%.
It would decrease by 8%.
It would increase, but not necessarily by 8%.
It would decrease, but not necessarily by 8%.
Answer:
It would decrease, but not necessarily by 8%
If the teacher had used a 90% confidence interval rather than a 98% confidence interval, the width of the interval would decrease, but not necessarily by 8%.
Option D is the correct answer.
What is a confidence interval?A confidence interval is a range of values that is likely to contain the true value of an unknown parameter, such as a population means or proportion, based on a sample of data from that population.
It is a statistical measure of the degree of uncertainty or precision associated with a statistical estimate.
We have,
The width of a confidence interval is determined by the level of confidence and the sample size.
A higher confidence level requires a wider interval, and a larger sample size typically results in a narrower interval.
Since the sample size is fixed in this case, changing the confidence level will result in a change in the width of the interval.
As the confidence level increases, the width of the interval also increases. This is because a higher confidence level requires a larger margin of error, which is added to the point estimate to create the interval.
Therefore,
If the teacher had used a 90% confidence interval rather than a 98% confidence interval, the width of the interval would decrease, but not necessarily by 8%.
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Kallen was invited to a birthday party for his best friend. He wanted to buy a gift that was $43.87 and wrapping paper that was $2.94. If he earns $8.25 for each lawn he mows and his mom agrees to match all his earnings how many lawns will he need to complete to buy the gift and wrapping
Answer: 6
Step-by-step explanation:
The total amount needed by Kallen for the gift and the wrapping paper will be:
= $43.87 + $2.94
= $46.81
Since he earns $8.25 for each lawn he mows, the number of lawns they he will need to complete to buy the gift and wrapping will be:
= $46.81 / $8.25
= 5.67
= 6 lawns approximately
He'll need to mow 6 lawns
Use synthetic division to determine whether the number is a zero of the polynomial function.
3i;g(x) = x^3 - 4x^2 + 9x - 36
The last entry in the synthetic division table is not zero, 3i is not a zero of the polynomial function g(x) = x³ - 4x² + 9x - 36.
To determine if 3i is a zero of the polynomial function g(x) = x³ - 4x² + 9x - 36, we can use synthetic division.
First, we set up the synthetic division table:
3i | 1 -4 9 -36
Performing the synthetic division:
| (1) (-4) (9) (-36)
3i | 3i 9i² 27i
| (1) (-4 + 3i) (9 + 9i²) (-36 + 27i)
Simplifying the last row, we have:
| (1) (-4 + 3i) (9 - 9) (-36 + 27i)
| (1) (-4 + 3i) (0) (-36 + 27i)
Therefore, the last entry in the synthetic division table is not zero, 3i is not a zero of the polynomial function g(x) = x³ - 4x² + 9x - 36.
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Find the measure of the exterior 1.
A. 144°
B. 56°
C. 36°
D. 136°
Plz help I’ll give brainliest
Answer:
2) 4/5
3) 3
Step-by-step explanation:
2) 4/8-3=4/5
3)5x-4=3x+2
2x=6
x=3
Answer:
2) 4/5
3)x=3
Step-by-step explanation:
1) 4/8-3= 4/5
2) 5x-4=3x+2
bring 3x to left side and bring -4 to right side (remember signs will be reversed that is 3x becomes -3x and -4 will be 4
5x-3x=4+2
2x=6
x=6/2
x=3
put 3 in place of x
5*3-4=3*3+2
15-4=9+2
11=11
let R be the region bounded by the functions f(x)=-x^2 and g(x)=-9 as shown in the diagram below. find the exact area of the region R. write your answer in the simplest form. zoom in photo
Justin completes 8 extra credit problems on the first day and then 4 problems each day until the worksheet is complete. There are 28 problems on the worksheet. Write and solve an equation to find how many days it will take Justin to complete the worksheet after the first day.
Answer:
28-8-4x=0
x=5
5 days
Step-by-step explanation:
28-8=20 problems left
then 4 each day
PLEASE HELP ME!!! I REALLY NEED TO KNOW THIS...
So my math teacher hates me and i did this for a answer:
5x³ + x² + 16 , this is a different question, and i got the points.
But for a answer that was right and she mared wrong i did this:
2x²+4
(I know it is right because my sister and me have the same math. and she got a 10/10 on this)
My sister's answer : 2x^2 + 4.
Are they the same or not?!
Answer:
The exact same
Step-by-step explanation:
^ just means put it up like 3^2=3²
Help help help help help
Answer:
6 ft
Step-by-step explanation:
The triangle CDE is half of the size of triangle ABC, so if you match up the corresponding sides, DE is half of AC. AC is 12 so DE is 6.
hope is helped!
a rectangle with a length of 20 meters and a width of 11 meters is being dilated by a scale factor of 5. What is the length of the rectangle after the dilation?
Answer:
We meet again
Step-by-step explanation:
When a rectangle is dilated by a scale factor k, the length and width of the rectangle are both multiplied by k. In this case, the length of the rectangle is being dilated by a scale factor of 5. So the length of the rectangle after the dilation will be 20 * 5 = **100 meters**.
SOMEONE PLEASE HELP I'VE BEEN ASKING FOR DAYS NOW WITH SCALE FACTOR!!!!! I will give brainliest if right!!!!!!
Answer:
It has been answered for you
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A scientist used 60 grams of sodium nitrate during an experiment. One ounce is approximately equal to 28.3 grams. Which measurement is closest to the number of ounces of sodium nitrate the scientist used?
Answer:
2
Step-by-step explanation:
60 divided by 28.3 which gives u 2.120141342756184
so round it which gives u 2
i need help i will give branliest please !!!
what is the solution
a: (6,5)
b: (5,6)
c: (1,2)
d: (2,1)
Answer:
(5,6)
Step-by-step explanation:
I'm guessing you mean the coordinates for the point where the lines intersect
Answer:
I believe it is b: (5,6)
Explanation:
The point (5,6) is the only point on the graph that both lines go through.
consider recurrence (and no such that for every non negative integer ny 2 an = 400-1 - 5an-2 +200-3 suppose recurrence (an) has the following initial value a=1 a2=2 in what follows, let a (n) dehote term an for each nonnegative integern write an explicit formula for a(n)
The given recurrence relation is an = 400 - 5an-2 + 200-3, with initial values a0 = 1 and a1 = 2. We need to find an explicit formula for a(n).
To find an explicit formula for a(n), we will first solve the recurrence relation and then generalize the pattern. Let's expand the relation for a few terms to observe the pattern:
a2 = 400 - 5a0 + 200-3 = 400 - 5(1) + 200-3 = 397
a3 = 400 - 5a1 + 200-3 = 400 - 5(2) + 200-3 = 388
a4 = 400 - 5a2 + 200-3 = 400 - 5(397) + 200-3 = -9603
a5 = 400 - 5a3 + 200-3 = 400 - 5(388) + 200-3 = -1260
From the given examples, we can observe that the recurrence relation alternates between positive and negative values. This suggests that the relation might have a periodic pattern. Since the given recurrence is a second-order relation (in terms of n), it is reasonable to assume that the pattern repeats every two terms.
Based on this observation, we can establish the following explicit formula for a(n):
a(n) = (-1)^(n mod 2) * (200n - 5^(n/2) + 200-3)
In this formula, the term (-1)^(n mod 2) alternates between -1 and 1 depending on the parity of n, ensuring the alternating pattern. The other terms account for the linear and exponential components of the recurrence relation.
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Right answer will be marked brainlist .
Robert takes out a loan for $7200 at a 4.3% rate for 2 years. What is the loan future value?
Answer: should be 7819.20
explanation:
7200 * .043 * 2 = 619.20
7200 + 619.20 = 7819.20
4. Evaluate the expression for the given value of each variable.
5a2 -7 -b3
when a = -2 and b = -3
please help!
NO LINKS!!!
Answer:
-18
Step-by-step explanation:
5a2-7-b3
[tex]5*a*2-7-b*3[/tex]
[tex]5\cdot \left(-2\right)\cdot \left(2\right)-7-\left(-3\right)\cdot 3[/tex]
Therefore, -18 is your answer.
Hope this helped! :)
34.607 to the nearest whole number
Leo flips a paper cup 50 times and records how the cup landed each time. The table below shows the results. RESULTS OF FLIPPING PAPER CUP Outcome Right-side UP Upside Down On its Side Frequency 10 18 22 Based on the results, how many times can he expect the cup to land on its side if it is flipped 1,000 times? 333 440 550 786
Answer:
The answer is 440
Step-by-step explanation:
I just took the test and got that question right
Which equation is not equivalent to 2x+10=-8
Answer:
2x+10=-8
x=9
3x=9
x=3
2x=8
x=4
4x=20
x=5
Step-by-step explanation:
Let f be the function given by f(x) = 2 cos x +1. What is the approximation for f(1.5) found by using 1 the tangent line to the graph off at x = ? 2 (A) -2 (B) 1 (C) 1-2 (D) 4-2
To approximate the value of f(1.5) using the tangent line to the graph of f at x = 1, we first find the derivative of f(x) to determine the slope of the tangent line at x = 1. The derivative is f'(x) = -2 sin x. Evaluating f'(x) at x = 1, we find the slope to be approximately -1.6829.
Next, we use the point-slope form of a line to find the equation of the tangent line. We have the point (1, f(1)) ≈ (1, 1.5839) and the slope -1.6829. Plugging these values into the point-slope form, we obtain the equation of the tangent line as y ≈ -1.6829x + 3.2668.
Finally, we substitute x = 1.5 into the equation of the tangent line to approximate f(1.5). After calculation, we find that f(1.5) is approximately 0.0009.
Therefore, the approximation for f(1.5) using the tangent line to the graph at x = 1 is approximately 0.0009.
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Help me plz!! I need help and NO FILES PLZZZZZZZ!
Answer:
1
EXPLAINATION:
y = mx +b
b = y intercept
Find the value of x that makes the equation true:
16 - x = 4
x = 18
x = 20
x = 14
x = 12
Why is it important to know "first term" and "common ratio" when dealing with geometric sequences?
Answer:
Each term of a geometric sequence increases or decreases by a constant factor called the common ratio. The sequence below is an example of a geometric sequence because each term increases by a constant factor of 6. Multiplying any term of the sequence by the common ratio 6 generates the subsequent term.
Step-by-step explanation:
Please give brainliest
please help me
Step-by-step explanation:
mark me brilliant
What's the slope and y intercept of 3x - y = 7
Answer:
the slope is 3
the y intercept is (0,-7)
Step-by-step explanation:
3x-y=7 solve for y
add y to both sides
3x=7+y
subtract 7 from both sides
y=3x-7
y=mx+b
m=slope
b=y-intercept
3=slope
-7=y-intercept
Hope that helps :)
The null hypothesis is that the laptop produced by HP can run on an average 120 minutes without recharge and the standard deviation is 25 minutes. In a sample of 50 laptops, the sample mean is 130 minutes. Test this hypothesis with the alternative hypothesis that average time is not equal to 120 minutes. What is the p- value?
The p-value for testing the hypothesis that the average runtime of HP laptops is not equal to 120 minutes, based on a sample mean of 130 minutes from a sample of 50 laptops, is approximately 0.0006 (rounded to four decimal places).
To calculate the p-value, we use the t-test. Given the null hypothesis that the average runtime is 120 minutes, the alternative hypothesis is that it is not equal to 120 minutes. We compare the sample mean to the hypothesized population mean using the t-distribution.
Using the formula for the t-statistic:
t = (sample mean - hypothesized mean) / (sample standard deviation / sqrt(sample size))
t = (130 - 120) / (25 / sqrt(50))
t = 10 / (25 / 7.0711)
t = 2.8284
The degrees of freedom for the t-distribution are (sample size - 1) = (50 - 1) = 49.
Using the t-distribution table or statistical software, we find that the two-tailed p-value for a t-value of 2.8284 with 49 degrees of freedom is approximately 0.0006.
Therefore, the p-value for this hypothesis test is approximately 0.0006.
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