Mathematics challenge

Answer:

The average function [tex]f_{avg}[/tex] value = 4

Step-by-step explanation:

Given that:

[tex]f(x,y,z) = 3x^2z+3y^2z[/tex]

The enclosed region [tex]z = 4 -x^2 -y^2[/tex] and the plane z = 0.

Over an area E, the average value of a function f(x,y,z) is:

[tex]f_{avg} = \dfrac{1}{V_{E}} \iiint_E f(x,y,z) dV ------ (1)[/tex]

where;

[tex]V_E[/tex] = volume of region E

To find the volume use cylindrical coordinates;

[tex]x=rcos \theta; \ \ \ y = rsin \theta; \ \ \ z = z[/tex]

Then;

E = 0 ≤ r ≤2, 0 ≤ θ ≤ 2π, 0 ≤ z ≤ 4 - r²

[tex]V_E = \int^{2 \pi}_{0} \int^{2}_{0} \int^{4-r^2}_{0} \ rdzdrd \theta[/tex]

[tex]V_E = \int^{2 \pi}_{0} \int^{2}_{0} r(4-r^2) \ drd \theta[/tex]

[tex]V_E = \int^{2 \pi}_{0} \int^{2}_{0} (4r-r^3) \ drd \theta[/tex]

[tex]V_E = \int^{2 \pi}_{0} \Big(2r^2- \dfrac{r^4}{4} \Big)^2_0 \ d \theta[/tex]

[tex]V_E = 4(2 \pi)\\\\ V_E = 8 \pi[/tex]

However, from equation (1):

[tex]f_{avg} = \dfrac{1}{V_E} \iiint_E f(x,y,z) \ dV \\ \\ = \dfrac{1}{8 \pi} \iiint_E (3x^2z + 3y^2 z) dV \\ \\ = \dfrac{1}{8 \pi } \int^{2 \pi}_{0} \int^{2 }_{0} \int^{4 - r^2}_{0} \ \ 3zr^2 \ rdzdrd\theta \\ \\ = \dfrac{3}{8 \pi} \int^{2 \pi}_{0} \int^{2 }_{0} \Big(\dfrac{z^2}{2}\Big)^{4-r^2}_{0} \ r^3 drd\theta \\ \\ = \dfrac{3}{16 \pi} \int^{2 \pi}_{0} \int^{2 }_{0} (4-r^2)^2 \ r^3 \ dr d\theta[/tex]

[tex]= \dfrac{3}{16 \pi} \int^{2 \pi}_{0} \int^{2 }_{0} (16-8r^2 + r^4)r^3 \ dr d\theta \\ \\ = \dfrac{3}{16 \pi} \int^{2 \pi}_{0} \int^{2 }_{0} (16r^3 -8r^5 + r^7) \ dr d \theta \\ \\ = = \dfrac{3}{16 \pi} \int^{2 \pi}_{0} \Big (4r^4 - \dfrac{8}{6}r^6 + \dfrac{r^8}{8} \Big)^2_0 \ d \theta \\ \\ = \dfrac{3}{16 \pi } (2 \pi) \Big (64 - \dfrac{8}{6} \times 64 \times \dfrac{256}{8} \Big) \\ \\ = \dfrac{3}{16 \pi} (2 \pi) (\dfrac{32}{3}) \\ \\ = 4[/tex]

Answer: 20 mangoes.

Step-by-step explanation: This is a simple subtraction problem. If you take away 8 from 28, you'll have 20.

28 - 8 = 20

Answer:

We reject the null hypothesis and accept the alternate hypothesis, that is, that the mean is less than 13 ounces.

Step-by-step explanation:

The null hypothesis is:

[tex]H_{0}: \mu = 13[/tex]

The alternate hypotesis is:

[tex]H_{a}: \mu < 13[/tex]

The test statistic is:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, [tex]\sigma[/tex] is the standard deviation and n is the size of the sample.

13 is tested at the null hypothesis:

This means that [tex]\mu = 13[/tex]

N(µ,0.42)

This means that the standard deviation is 0.42, that is, [tex]\sigma = 0.42[/tex]

You collect a random sample of n = 35 boxes and find that the sample mean is 12.8.

This means that [tex]n = 35, X = 12.8[/tex]

Value of the test statistic:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

[tex]z = \frac{12.8 - 13}{\frac{0.42}{\sqrt{35}}}[/tex]

[tex]z = -2.82[/tex]

Pvalue of the test:

The pvalue of the test is the pvalue of z = -2.82.

Looking at the z table, z = -2.82 has a pvalue of 0.0024

0.0024 < 0.01, which means that we reject the null hypothesis and accept the alternate hypothesis, that is, that the mean is less than 13 ounces.

Answer:

18 x 6 =108. she spent 108 minutes reading.

Step-by-step explanation:

Answer:

I think its B

Hope this helps

Answer:

A standard deck of cards consists of 52 cards. The colors are usually black for the spades and clubs and red for the hearts and diamonds.

Step-by-step explanation:

Answer:

There are 52 cards which are either red or black

Step-by-step explanation:

Answer:

The first choice

Step-by-step explanation:

Answer:-1

Step-by-step explanation:

2.5+(-4.5) then / 2

Answer:

9

Step-by-step explanation:

you would do 3+3+3 because there are 3 colors

And i just got it right on my quiz.

There will be 9 branches in the tree diagram of the situation.

In probability theory, tree diagrams can be used to represent probability spaces. A tree diagram can represent a set of independent events or conditional probabilities. Each node in the graph represents an event and is associated with the probability of that event.

Given,

A spinner of three sections colored green, purple and pink.

Number of outcomes = 3

spinner is spun twice,

then number of outcomes = 3 × 3 = 9

Number of branches in tree = 9

Hence, 9 branches will be there in probability tree diagram.

Learn more about tree diagram here:

https://brainly.com/question/13311154

#SPJ6

Answer:

1. 1/6 2. 80

Step-by-step explanation:

Answer:

Step-by-step explanation:

People started getting stimulus checks during the time when c0vid-19 was a major issue because most places where people would work were closed, so people were getting money through stimulus checks because they were basically unemployed. This money went back into the economy to buy mostly essentials and health products, so therefore it helped businesses that sold these kinds of things.

Answer:

(2;-2)

Step-by-step explanation:

for more details see the attached picture.

Answer:

No, it is not a valid way

Step-by-step explanation:

Required

Is Susie's method valid?

Susie's method worked because 4 & 7 and 3 & 5 do not have a common factor.

In other words, Susie's method will not work when the two numbers have a common factor.

Take for instance, the LCM of 2 and 4.

Using Susie's method, the LCM will be 8 (i.e. 2 * 4) whereas the LCM is 4.

Answer:

One proportion is 15 songs / 2.5 hours = 18 songs / h hours.

ok I'll try to answer

first the given 15/2.5=18/h

so the second hour is missing so we have to multiply cross then the result will be

15h=45

divide 15 for 15 and we got h

again divide 45 for 15

[h=3]

Step-by-step explanation:

area of a rectangle bh

4x7=28

7x9=63

9x4=36

the only rectangle that has an area equal to 28 is the 4x7 which is the front face and back face.

Hope that helps :)

Answer:  (A)-2, -1

(b) 3,0

(C) 7,2

Step-by-step explanation:

So you just go and write the place and which ever one isnt there then theres you answer. I THINK

Answer:

3/6 or 1/2

Step-by-step explanation:

the amount that chose pizza = 2/6

5/6 = the amount that chose pizza + the amount that chose tacos

5/6 = 2/6 + the amount that chose tacos

the amount that chose tacos = 5/6 - 2/6

the amount that chose tacos = (5-2)/6

the amount that chose tacos=3/6=1/2

Answer:

3/6

Step-by-step explanation:

Answer:

area of triangle = 1/2×base×height

area of triangle =1/2×15m×16m

area of triangle =120m²

Answer:

Step-by-step explanation:

Answer:

Step-by-step explanation:

t is the number of years since 2003.

f(t) = $18,500×0.88^t

t = 2 in 2005

f(2) = $18,500×0.88²≅ $14,300

Answer:

$14300.00

Step-by-step explanation:

100 - 12 = 88%

88% = 0.88

$18500 x 0.88² = $14326.40

To the nearest hundread:

$14326.40 = $14300.00

0.88² means to the power of 2 since it is 2 consecutive years I did to the power of 2. If it was 3 consecutive years then you do 0.88³.

Hope this helps!

Answer:

36.84

Step-by-step explanation:

just add them it is all really just basic addition nothing more to it

Answer:

hope this helps :)

Step-by-step explanation:

Answer: 1.333

Step-by-step explanation:

Answer:

1.33

Step-by-step explanation:

nothing much to explain

Answer:

don't listen to the other person

Step-by-step explanation:

Answer:x=18

Step-by-step explanation:

if she deposites 40 every week 40 times 18 is 720 so in 18 weeks she can have a t.V

Answer:

An arithmetic sequence has a constant difference between each term. ... A geometric sequence has a constant ratio (multiplier) between each term. An example is: 2,4,8,16,32,… So to find the next term in the sequence we would multiply the previous term by 2.

Step-by-step explanation:

Answer:

(6,1) is the correct answer

Answer: (-2,5)

Step-by-step explanation:

Answer:

62.16

Step-by-step explanation:

Answer:

l=8/3h equation demonstrates this

Answer:

Owen has $71 and Ethan has $104

Step-by-step explanation:

Create a system of equations where o is how much money Owen has, and e is how much Ethan has

x + e = 175

e = x + 33

Solve by substitution by plugging in o + 33 in as e, in the first equation

o + e = 175

o + (o + 33) = 175

2o + 33 = 175

2o = 142

o = 71

So, Owen has $71 dollars

To find how much Ethan has, add 33 to this, since he has $33 more than Owen

71 + 33

= 104

So, Owen has $71 and Ethan has $104