A random variables X and Y are distributed according to the joint PDF. The value of constant a = _______.f(x,y)=ax if 1<=1x<=y<=2 and 0 otherwise

Answers

Answer 1
Answer:    3/2

======================================================

Explanation:

PDF = probability density function

The given joint PDF is

[tex]f(x,y) = \begin{cases}ax \ \ \ \text{ if } 1 \le x \le y \le 2\\0 \ \ \ \ \ \text{ otherwise}\end{cases}[/tex]

Let's focus on the [tex]1 \le x \le y \le 2[/tex]. Specifically the x term for now. Erasing out the y term, we have the inequality [tex]1 \le x \le 2[/tex] which says x is between 1 and 2, inclusive. We have almost the same story for y, but there's another condition attached to it: y must also be equal to or larger than x.

So let's say x = 1.5. This would mean [tex]1.5 \le y \le 2[/tex]. As another example, x = 1.7  leads to [tex]1.7 \le y \le 2[/tex]. In general, we would say [tex]x \le y \le 2[/tex] where x is between 1 and 2.

As x gets bigger, the range of possible y values gets smaller. If x = 2, then y has no choice but to be 2 as well.

-----------------

Based on that, we'll have a double integral that looks like this:

[tex]\displaystyle V = \int_{1}^{2}\int_{x}^{2}f(x,y)dydx\\\\[/tex]

The outer integral handles the x terms that range from 1 to 2, describing [tex]1 \le x \le 2[/tex]. Note the dx on the outside. The order of the dy and dx matters.

On the inside, we have the integral for dy ranging from x to 2 to describe the interval [tex]x \le y \le 2[/tex]

To have f(x,y) be a PDF, the volume under the f(x,y) surface must be 1, where the volume is based on the bounds set up. So we must have V = 1. We'll use this later.

-----------------

Let's simplify the double integral.

We'll start by computing the inner integral with respect to y.

[tex]\displaystyle V = \int_{1}^{2}\int_{x}^{2}f(x,y)dydx\\\\\displaystyle V = \int_{1}^{2}\int_{x}^{2}\left(ax\right)dydx\\\\\displaystyle V = \int_{1}^{2}\left(axy\Bigg|_{x}^{2}\right)dx\\\\\displaystyle V = \int_{1}^{2}\left(ax(2) - ax(x)\right)dx\\\\\displaystyle V = \int_{1}^{2}\left(2ax - ax^2\right)dx\\\\[/tex]

Then we'll finish it off by integrating with respect to x.

[tex]\displaystyle V = \int_{1}^{2}\left(2ax - ax^2\right)dx\\\\\displaystyle V = \left(ax^2 - \frac{1}{3}ax^3\right)\Bigg|_{1}^{2}\\\\\displaystyle V = \left(a(2)^2 - \frac{1}{3}a(2)^3\right) - \left(a(1)^2 - \frac{1}{3}a(1)^3\right)\\\\\displaystyle V = \left(4a - \frac{8}{3}a\right)-\left(a - \frac{1}{3}a\right)\\\\[/tex]

[tex]\displaystyle V = 4a - \frac{8}{3}a-a + \frac{1}{3}a\\\\\displaystyle V = 3a - \frac{8}{3}a + \frac{1}{3}a\\\\\displaystyle V = \frac{9}{3}a - \frac{8}{3}a + \frac{1}{3}a\\\\\displaystyle V = \frac{9-8+1}{3}a\\\\\displaystyle V = \frac{2}{3}a\\\\[/tex]

Side note: We don't have to worry about the "plus C" integration constant when working with definite integrals.

Recall that V = 1. So,

[tex]\displaystyle V = \frac{2}{3}a\\\\\displaystyle \frac{2}{3}a = 1\\\\\displaystyle a = \frac{3}{2} = 1.5\\\\[/tex]

a = 3/2 is the final answer.


Related Questions

can help my little bro

Answers

Answer:

$0.03

Step-by-step explanation:

chips: 7.84/16=0.49

pretzels: 12.48/24=0.52

0.52=0.49=0.03

what is the value of x in m(x+n)=n​

Answers

The equation m(x + n) = n​ si solved for x will be given as x = n / m (1 - m).

What is the linear system?

A linear system is one in which the parameter in the equation has a degree of one. It might have one, two, or even more variables.

The equation is given below.

m(x + n) = n​

By simplifying for x, then we have

x + n = n / m

     x = n / m - n

     x = (n - mn) / m

     x = n / m (1 - m)

More about the linear system link is given below.

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Larry is using an online calculator to calculate the outputs f(n) for different inputs n. The ordered pairs below show Larry's inputs and the corresponding outputs displayed by the calculator: (1, 5), (2, 9), (3, 13), (4, 17) Which of the following functions best represents the rule that the calculator uses to display the outputs?

Answers

Answer: The answer is c. f(n)=4n+1

Graph the equation of the line parallel to 2x−y=6 and passing

through (-3, 1). Show work.

Answers

Answer:

It's a graph, see the image.

Step-by-step explanation:

Use the equation to find the slope. Use the slope and the point to graph the line.

three hundred two times one hundred fifty three
302×153​

Answers

Answer:

46,206

Step-by-step explanation:

simple math

Answer:

the answer is 46,206

Step-by-step explanation:

Good luck!!!!

Suppose a quadratic equation has the form x^2 + x + c = 0. Show that the constant c must be less than 1/4 in order for the equation to have two real solutions.

Answers

Answer:

see explanation

Step-by-step explanation:

Given a quadratic equation in standard form

ax² + bx + c = 0 ( a ≠ 0 )

Then for the equation to have 2 real roots , the discriminant must be greater than zero , that is

b² - 4ac > 0

x² + x + c = 0 ← is in standard form

with a = 1, b = 1, c = c , then

b² - 4ac > 0

1² - (4 × 1 × c) > 0

1 - 4c > 0 ( subtract 1 from both sides )

- 4c > - 1

Divide both sides by - 4, reversing the inequality as a result of dividing by a negative quantity.

c < [tex]\frac{1}{4}[/tex]

Pls need help
Also making this 10 points so i have 169 points left B)

Answers

Answer:

Second and fourth

Step-by-step explanation:

A line is in point-slope form when you write down as [tex]y-y_0=m(x-x_0)[/tex] - do not be distracted by the signs, +1 and +5 can both be written as -(-1) or -(-5) rispectively.

Kevin will be taking six classes next semester (Algebra, World History, Psychology, Political Science, Chemistry, and Art Theory) and would like to know how many different ways he can order his class schedule given that his university offers six time slots for classes each day. Assuming there are no constraints and each class can be taken in any time slot, how many different ways can Kevin order his classes?

Answers

Answer:  720

=========================================================

Explanation:

We have 6 slots to fill A,B,C,D,E,F

There are 6 choices for choice A, then 5 choices for slot B, 4 for C, and so on until we reach one choice for slot F. Count down by 1 each time a slot is filled.

Multiply out those values to get: 6*5*4*3*2*1 = 720

For more information, check out the concept of factorials.

---------

Another approach is to use the nPr permutation formula which is

[tex]_nP_r = \frac{n!}{(n-r)!}[/tex]

where in this case n = 6 and r = 6.

What's The Interest Rate?
I = $200
P = $800
T = 24 months

Answers

I think it is $200 because there is a I next to it so Stands for Intreat rate

Mark’s birthday is 32 weeks away. How many days until his birthday?

Answers

There are 7 days in one week
So multiply 32 by 7

32*7 =224 days


In Manhattan, there are 15 CoffeeStops per 100,000 people Manhattan has approximately 1,602,000 people How many Coffee Stops are there?

Answers

Answer:

Given that 15coffee stops=100,000people

then: x= 1,602,000

100,000×x= 15×1,602,000

100,000x= 24,030,000

100,000x÷100,000= 24,030,000÷100,000

x= 240.3

so therefore there are 240.3 coffee stops if there are 1,602,000

Manhattan has approximately 1,602,000 people. Then the number of coffee shops will be 241.

What are ratio and proportion?

A ratio is a collection of ordered integers a and b represented as a/b, with b never equaling zero. A proportionate expression is one in which two items are equal.

In Manhattan, there are 15 CoffeeStops per 100,000 people.

Then the number of coffee shops per person will be

⇒ 15 / 100,000

⇒ 1.5 × 10⁻⁴ coffee shops per person

Manhattan has approximately 1,602,000 people.

Then the number of coffee shops will be

⇒ 1,602,000 × 1.5 × 10⁻⁴

⇒240.3 or 241 coffee shops

Manhattan has approximately 1,602,000 people. Then the number of coffee shops will be 241.

More about the ratio and the proportion link is given below.

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You have a Rectangle with sides of 5ft and 8ft; solve for its perimeter and area.

Answers

Answer:

Perimeter = 2(l+w) = 2*(5+8) = 26ft

Area = wl = 8*5 = 40

Step-by-step explanation:

pretty sure :)

can anyone help me please just cat get it​

Answers

Answer:

it is c I think if not sorry

[tex]~\hspace{10em}\textit{function transformations} \\\\\\ \begin{array}{llll} f(x)= A( Bx+ C)^2+ D \\\\ f(x)= A\sqrt{ Bx+ C}+ D \\\\ f(x)= A(\mathbb{R})^{ Bx+ C}+ D \end{array}\qquad \qquad \begin{array}{llll} f(x)=\cfrac{1}{A(Bx+C)}+D \\\\\\ f(x)= A sin\left( B x+ C \right)+ D \end{array} \\\\[-0.35em] ~\dotfill[/tex]

[tex]\bullet \textit{ stretches or shrinks horizontally by } A\cdot B\\\\ \bullet \textit{ flips it upside-down if } A\textit{ is negative}\\ ~~~~~~\textit{reflection over the x-axis} \\\\ \bullet \textit{ flips it sideways if } B\textit{ is negative}\\ ~~~~~~\textit{reflection over the y-axis}[/tex]

[tex]\bullet \textit{ horizontal shift by }\frac{ C}{ B}\\ ~~~~~~if\ \frac{ C}{ B}\textit{ is negative, to the right}\\\\ ~~~~~~if\ \frac{ C}{ B}\textit{ is positive, to the left}\\\\ \bullet \textit{ vertical shift by } D\\ ~~~~~~if\ D\textit{ is negative, downwards}\\\\ ~~~~~~if\ D\textit{ is positive, upwards}\\\\ \bullet \textit{ period of }\frac{2\pi }{ B}[/tex]

now keeping that template for transformations above in mind, let's take a look at this one

[tex]\stackrel{\textit{original}}{f(x) = |x|}\implies f(x)=\stackrel{A}{1}|\stackrel{B}{1}x+\stackrel{C}{0}|+\stackrel{D}{0}[/tex]

now, the vertex of this type, or original that'll be the origin at (0,0), and its' graph looks like a V.

now let's take a peek at the graph, hmmm from the original V-shape it moved to the left by 2 units, with a horizontal shift of C/B = 2, we can say that +2/1 gives B = 1 and  C = +2, and moved upwards by 3 units, namely D = +3.

we can also see that it flipped upside-down over the horizontal(x-axis), namely A is negative, on all choices the only value we see for A is "4", so it must be that A = -4

let's plug all those in

[tex]\begin{cases} A=-4\\ B=1\\ C=+2\\ D=+3 \end{cases}\qquad f(x)=\stackrel{A}{-4}|\stackrel{B}{1}x+\stackrel{C}{2}|+\stackrel{D}{3}\implies f(x)=-4|x+2|+3[/tex]

NEED NOW PLEASE.....

Answers

Answer:

2+(-6)

Step-by-step explanation:

hope this helps

Talia’s Australian Shepherd weighed 11 pounds when they first brought him home. By the time he was 6 months old, he weighed 33 pounds. What is the percent increase? *

Answers

Answer:

11+ 200% = 33 pounds

The percent increase is 200%

Step-by-step explanation:

A room has a rectangular floor 5.5 m long and 4.5 m wide. The room is 2.5 m in height.

A. What is the area of wall space in the room?

B. How much paint is required to paint the

walls with two coats if one litre of paint
can cover 11.25 m??

Answers

Answer:

Length=8 m,Breadth=6 m,Height=3 m

We know,

LSA=2(l+b)×h

LSA=2×14×3=84 m

2

Therefore, cost of painting = 84×60=Rs.5040.

Which triangle has vertices (–3, –5), (7, 4), (0, 4)?

Answers

Answer:

  see attached

Step-by-step explanation:

The one that matches the triangle shown in the attachment has the given vertices.


2. If Jordan's section contains 35 rows, how many seats are in her section?
seat(s)

Answers

Answer:

5

Step-by-step explanation:

Write the equation of the line perpendicular to y = 8 - 5z that contains the point (0, 0) . Fill in the slope and y-intercept

Answers

The equation of the line perpendicular to y = 8 - 5z is 5x+8y=16.

8y=-5x+16

y=-5/8x+2.

To be perpendicular, the slope has to be 8/5.

What is the slope-intercept form of the line?

The slope-intercept form is y=mx+c

Where m is the slope and c is the y-intercept.

So y=8/5x+b.

We can plug in the given coordinates to get

7=8/5*-5+b

7=-8+b

b=15.

So eqn is y=8/5x+15 or in point-slope form, y=8/5x+15

5y=8x+75

5y-8x=75

The equation of the line perpendicular to y = 8 - 5z is 5x+8y=16.

To learn more about the slope-intercept form visit:

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It takes 6 hours to clean and detail a luxury car. During the morning of
cleaning, the workers were able to clean for 4 hours. If the variable t stands
for the amount of time the workers have left to clean the windows after lunch,
which of the following units could apply to this variable?

Answers

The correct answer is hours
The correct answer is hours

11. Select the proper order from least to greatest for 2/3, 7/6, 1/8, 9/10.
O A.1/8, 2/3, 9/10, 7/6
O B.2/3, 9/10, 7/6, 1/8
O C.7/6,9/10, 2/3, 1/8
O D. 1/8, 9/10, 7/6, 2/3

Answers

Step-by-step explanation:

Option A is the correct answer

Answer:

A is correct

Step-by-step explanation:

[tex]\frac{1}{8}[/tex] is 0.125

[tex]\frac{2}{3}[/tex] is 0.667

[tex]\frac{9}{10}[/tex] is 0.9

[tex]\frac{7}{6}[/tex] is 1.167

which from this you can see that A represents the order from smallest to largest

This question on your unit test is a fill in the blank. Be prepared to type your answer. The graph show how many minutes it takes Ziah to run a certain distance in the city. What is the meaning of the point (4, 6)?​

Answers

The point (4,6) means it took Ziah 4 minutes to run 6 blocks.

This is because any point is of the form (x,y) where in this case

x = number of minutes

y = number of blocks

Please helppppp quick

Answers

Answer:

option C

Step-by-step explanation:

x + 5 ≤ 13

x + 5 - 5 ≤ 13 - 5

x = 8

Answer:

x  ≤  8

Step-by-step explanation:

Move all terms not containing  x to the right side of the inequality. Then solve for x. :)

Joshua's assignment this weekend is to read a book with seventy-four pages. On Saturday he read thirty pages. How many pages does he need to read on Sunday?

Answers

Answer:

61

Step-by-step explanation:

he read first 74 and need to

= 74-30

=44

6. Your gas tank can hold no more than 14.5 gallons of gasoline. On a trip to the grocery store, you use 1.5 gallons of gasoline. Write and solve an inequality that represents the amount of gasoline left in your gas tank after 2 trips to the grocery store.​

Answers

Answer:

14.5 ≥ g(1.5)

g = The number of trips to the grocery store.

You will have 11.5 gallons left.

Can someone help me please

Answers

Answer: 56 times

Pls mark brainleist i really need it

Dr. M wanted to estimate the mean cholesterol level for men living in Hartford. He took a sampled of 20 men from Hartford and found that mean cholesterol level is 86 with a standard deviation of 12. He wants to construct a 99 % confidence interval for mean cholesterol level of men.

In this case, the level of significance a and the critical value?​

Answers

Answer:

answer is in an image here

imageshare.best/image.php?id=JS9NDO

Explanation:

copy n paste in browser

not a bot btw

I need some help please

Answers

The answer is A.

A negative x a negative equals a positive so the square root of a negative value cannot be a negative value.

When divide f(x)=ax³+bx²+cx+d by (x+3), the remainder is 4, then what is the remainder when divide 2f(x)-6 by (x+3)?​

Answers

Answer:

2

Step-by-step explanation:

When divide f(x)=ax³+bx²+cx+d by (x+3), the remainder is 4:

f(x) = m*(x + 3) + 4, where m is the quotient

Then 2f(x) - 6 is:

2[m(x + 3) + 4] - 6 = 2m(x + 3) + 8 - 6 = 2m(x + 3) + 2

As we see the remainder is 2

Which is a composite number? A.97 B.89 C.95 D.13

PLEASE I REALLY NEED THE CORRECT ANSWER RIGHT NOW!!!!​

Answers

Answer: C. 95 is a composite number.

Step-by-step explanation:

You can look at the ones place of each number to see if any end in 0, 2, 5, or any other digit that indicates that the number is not prime. Since 95 ends in a 5, it can be divided by 5, making it have more factors than 1 and itself. Therefore, 95 is the composite number of the list of numbers.

Answer:95

Step-by-step explanation:composite numbers are numbers that have more factors than 1 and itself, factors are numbers you can multiply to get a number. 95 is a composite number since 1,95, AND 5 are all factors of 95 making it a composite number

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