A Cepheid variable star is a star whose brightness alternately increases and decreases. Suppose that Cephei Joe is a star for which the interval between times of maximum brightness is 5.3 days. Its average brightness is 2.9 and the brightness changes by /- 0.35. Using this data, we can construct a mathematical model for the brightness of Cephei Joe at time t, where t is measured in days:______.B(t)=4.2 +0.45sin(2pit/4.4)
(a) Find the rate of change of the brightness after t days.
(b) Find the rate of increase after one day.

Answers

Answer 1

Answer:

[tex]\dfrac{0.7\pi}{5.3}\cos(\dfrac{2\pi t}{5.3})[/tex]

0.16

Step-by-step explanation:

According to the question the mathematical model should be

[tex]B(t)=2.9+0.35\sin(\dfrac{2\pi t}{5.3})[/tex]

Differentiating with respect to time we get

[tex]B'(t)=0.35\cos(\dfrac{2\pi t}{5.3})\times(\dfrac{2\pi}{5.3})\\\Rightarrow B'(t)=\dfrac{0.7\pi}{5.3}\cos(\dfrac{2\pi t}{5.3})[/tex]

So, the rate of change of brightness after t days is [tex]\dfrac{0.7\pi}{5.3}\cos(\dfrac{2\pi t}{5.3})[/tex]

After 1 day means [tex]t=1[/tex]

[tex]B'(1)=\dfrac{0.7\pi}{5.3}\cos(\dfrac{2\pi\times 1}{5.3})\\\Rightarrow B'(1)=0.16[/tex]

The rate of increase after one day is 0.16.


Related Questions

Help please!! Inverse of Matrix problem!!

Number 8 please!!

Answers

Step-by-step explanation:

Inverse of p matrix is in picture

i wish it will make u easy to do♥️✌️

Anna worked worked 37 hours this week at £8.97 hour. she then worked nine hours overtime at time and a half. how much does she get paid in total? round your answer to the nearest pound.​

Answers

417

Step-by-step explanation:

I hope this helps :)

Convert 0.49494949 into a fraction. Show all work.

Answers

Answer:

0.49 49

=

49      this is a fraction

99

Step-by-step explanation:

Let

XXX

x

=

0.49

¯¯¯¯

49

then

XXX

100

x

=

49.49

¯¯¯¯

49

and

XXX

99

x

=

100

x

x

=

49

XXX

x

=

49

99

Where would you locate √6 on the number line?...
Between 2.75 and 3.0
Between 2.5 and 2.75
Between 2.0 and 2.25
Between 2.25 and 2.5​

Answers

Answer:

Between 2.25 and 2.5

Step-by-step explanation:

The square root of 6 is 2.4494.... which is closer to 2.5

Find the value of x.
930
45°
X=
help please

Answers

Answer:

45 Degrees

Step-by-step explanation:

Compare to its other side

180°-138°=42°
Hope this helps

a cyclist travels 14 hours in per hour. what is the cyclists speed in feet/ minute. 1 mile= 5280 feet

Answers

Answer:

1,232 ft/min (feet per minute)

Step-by-step explanation:

14 miles = 73,920 feet

1 hour = 60 minutes

73, 920 / 60 = 1,232 feet/minute

1. The mean number of siblings for respondents in a survey is 3.76 with a standard deviation of 3.18. Calculate the Z score associated with 3 siblings. Your answer should be rounded to two decimal places, like 5.43 or 1.30.
2. The mean number of siblings for respondents in a survey is 3.76 with a standard deviation of 3.18. Using the standard normal table, calculate the proportion of respondents who had more than 2 siblings. Your answer should be rounded to two decimal places, like 0.43 or 0.30.

Answers

Answer:

-0.24 ; 0.71

Step-by-step explanation:

Given that :

Mean number of siblings (m) = 3.76

Standard deviation (s) = 3.18

Z score associated with 3 siblings

x = 3

Using the relation :

Zscore = (x - m) / s

Zscore = (3 - 3.76) / 3.18

Zscore = - 0.76 / 3.18

Zscore = −0.238993

Zscore = - 0.24

2.) proportion of respondents with more than 2 siblings

Using the z probability calculator :

X > 2

Obtain the standardized score :

Zscore = (x - m) / s

Zscore = (2 - 3.76) / 3.18

Zscore = - 1.76 / 3.18

Zscore = −0.5534591

Zscore = - 0.55

Using the z table :

P(Z ≥ - 0.55) = 1 - p(Z ≤ - 0.55) ; p(Z ≤ - 0.55) = 0.2912

1 - p(Z ≤ - 0.55) = 1 - 0.2912 = 0.7088 = 0.71

One number is 4 more than 3 times another. Their sum is 16. Find the two numbers.

Answers

I think the answer is 4 + 3x = 16

Please help me really need help please please will mark brainiest it’s due today at 3:30pm please help me please

Answers

Answer:

8 Hours.

Step-by-step explanation:

-25.63+ -30.59 ??? Can someone let me know what this equals?

Answers

Answer:

= -56.22

Step-by-step explanation:

have a great day

pls mark as brainliest!

hope this helped!

Answer:

-56.22

just calculated it (:

help me with this question if you don’t mind❗️

Answers

Answer:

12m by 3m

Step-by-step explanation:

lol please mark brainliest

a piece of metal has a mass of 2210g the volume of the metal is 260cm3 what is the density of the piece of metal​

Answers

Answer:

The density is 8.5 g/cm³

Step-by-step explanation:

The density formula is density = mass/volume

When we plug our numbers into the formula, we get:

Density = 2210 / 260

We can then solve and get our answer 8.5 g/cm³

It is given a piece of metal has a mass of 2210g the volume of the metal is 260cm ^3 . The density is 8.5 g/cm³.

How are density, volume and mass of a substance related?

Suppose that a finite amount of substance is there having its properties as:

The mass of substance = m kg

The density of substance = d kg/m³

The volume of that substance = v m³

Then, they are related as:

[tex]d = \dfrac{m}{v}[/tex]

It is given a piece of metal has a mass of 2210g the volume of the metal is 260cm ^3 .

density = mass/volume

When we substitute our numbers into the formula, we get:

Density = 2210 / 260

Density = 8.5 g/cm³

It is given a piece of metal has a mass of 2210g the volume of the metal is 260cm ^3 . The density is 8.5 g/cm³

Learn more about mass, volume and density relation here:

https://brainly.com/question/952755

#SPJ5

What is the reciprocal of 8 5/6​

Answers

Answer:

6/53

Step-by-step explanation:

I think the Awnser is 6/53 I’m not sure

Name a street that is perpendicular to Hwy 64/40 . Can you help with all these questions

Answers

Answer:

no puedo alludar te perdón

1+9 help me now plssssss

Answers

Your answer would be 10

Answer:

10

Step-by-step explanation:

you do the one plus the nine which gives you 11 then subtract 2 which gets you 9 then add 4 which gets you 13 then minus 3 which gets you 10.

Allison traveled a distance of 130 miles in 2
1
hours. What was Allison's average driving
speed, in miles per hour?

Answers

65 miles per hour Divide 130 by 2 and you’ll get 65mph :)

Allison's average driving speed in miles per hour is 65.

What is speed?

Speed is the ratio of distance and time.

It shows how fast an object is moving at a given time.

We have,

130 miles = 2 hours

Divide 2 on both sides.

130/2 miles = 1 hour

65 miles = 1 hour

Thus,

The average speed is 65 miles per hour.

Learn more about speed here:

https://brainly.com/question/7359669

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A device runs until either of two comonents fails, at which point the device stops running. The joint density function of the lifetimes of the two components, both measured in hours, is f(x,y) = x + y/8 for 0 < x < 2 and 0 < y < 2Calculate the probability that the device fails during its first hour of operation.

Answers

Answer:

The probability that the device fails during its first hour of operation is 0.625.

Step-by-step explanation:

The joint density function of the lifetimes of the two components, both measured in hours, is:

[tex]f(x,y)=\frac{x+y}{8};\ 0<x<2,\ 0<y<2[/tex]

Compute the probability that the device fails during its first hour of operation as follows:

[tex]P[(X<1)\cup (Y<1)]=1-\int\limits^{2}_{1} {\int\limits^{2}_{1} {\frac{x+y}{8}} \, dx } \, dy[/tex]

                                  [tex]=1-\int\limits^{2}_{1} {\frac{x^{2}+2xy}{16}}|^{2}_{1} \, dy\\\\=1- \int\limits^{2}_{1}[{\frac{4+4y}{16}-\frac{1+2y}{16}}] \, dy\\\\=1-\int\limits^{2}_{1}{\frac{3+2y}{16}}\, dy\\\\=1-[\frac{3y+y^{2}}{16}]^{2}_{1}\\\\=1-0.375\\\\=0.625[/tex]

Thus, the probability that the device fails during its first hour of operation is 0.625.

someoneeeeee pleaseeeeee help meeee​

Answers

Answer: x=60

Step-by-step explanation:

x+22+x+6+x−28=180

Step 1: Simplify both sides of the equation.

x+22+x+6+x−28=180

x+22+x+6+x+−28=180

(x+x+x)+(22+6+−28)=180(Combine Like Terms)  22+6=28 and then 28-28=0

3x=180  

3x=180

Step 2: Divide both sides by 3.

3x/3 = 180/3

x=60

hope this was helpful.

The graph of a proportional relationship will always be a straight line that passes through the origin. Why?

Answers

Answer:

Being proportional between two entities, refers to the 'Constant of Proportionality' that would be fixed between them which establishes a relationship between them when multiplied or divided.

If we considered it on a graph, the 'Constant Of Proportionality' may take any real values between the coordinate pairs x and y [x,y]. As even 0 is a real number, it will surely be a constant of proportionality when multiplied since its product would result in itself (0). Hence, both x and y turns 0.

As the coordinates of the origin are always (0,0), the graph  (Or the slope) would surely pass through the origin.

Example :

If we consider a graph such that x=y.

And if we multiply or divide any real number (a) between them.

ax=ay

As a is a variable, and can take the value of 0, the graph can pass through the origin as x and y nullify becoming the coordinates of the origin.

please help me solve this

Answers

Answer:

A) 7 and 8

Step-by-step explanation:

root of 7 is 2.64575..... then when u multiply by 3

3*2.64575=7.93725

Five more than a number is equal to seven-halves of the number What is the number?
HELP

Answers

Answer:

The number is 2

Step-by-step explanation:

To attempt this question, we need to represent the number with (x).

Let the number be x

Five more than the number is:

5 + x

Seven-halves means 1/2 × 7 = 7/2

Mathematically, the question is saying:

5 + x = 7/2 × x

5 + x = 7x/2

Cross multiply;

2(5 + x) = 7x

10 + 2x = 7x

We collect like terms;

10 = 7x - 2x

10 = 5x

x = 10/5

x = 2

The number represented by x is 2

We want to convert the given sentence into an equation, and then solve it. We will see that the number is 2.

Finding the equation

We start with the sentence:

"Five more than a number is equal to seven-halves of the number"

if we define x as the number, we can write:

5 + x = (7/2)*x

Now we can solve this equation for x, we will get:

5 + x = (7/2)*x

5 = (7/2)*x - x = (7/2 - 1)*x

5 = (7/2 - 2/2)*x = (5/2)*x

(2/5)*5 = x

2 = x

So the number is 2.

If you want to learn more about linear equations, you can read:

https://brainly.com/question/4074386

You have asked to design a rectangle box with a square base and an open top. The volume of the box must be620 cm to the 3rd power. the cost of the material for the base is $0.40 per square cm and the cost of the material for the side is $0.10 per square cm.How to determine the dimension of the box that will minimize the cost of manufacturing. What is the minimum cost? in dollars and rounded to the nearest cent.

Answers

Answer:

$69.21

Step-by-step explanation:

Since the box has a square base the length and breadth of the box will be equal. Let it be [tex]x[/tex]

Let h be the height of the box

V = Volume of the box = [tex]620\ \text{cm}^3[/tex]

[tex]x^2h=620\\\Rightarrow h=\dfrac{620}{x^2}[/tex]

Now surface area of the box with an open top is given

[tex]s=x^2+4xh\\\Rightarrow s=x^2+4x\dfrac{620}{x^2}\\\Rightarrow s=x^2+\dfrac{2480}{x}[/tex]

Differentiating with respect to x we get

[tex]\dfrac{ds}{dx}=2x-\dfrac{2480}{x^2}[/tex]

Equating with zero

[tex]0=2x-\dfrac{2480}{x^2}\\\Rightarrow 2x^3-2480=0\\\Rightarrow x^3=\dfrac{2480}{2}\\\Rightarrow x=(1240)^{\dfrac{1}{3}}\\\Rightarrow x=10.74[/tex]

Double derivative of the function

[tex]\dfrac{d^2s}{ds^2}=2+\dfrac{4960}{x^3}=2+\dfrac{4960}{1240}\\\Rightarrow \dfrac{d^2s}{ds^2}=6>0[/tex]

So, x at 10.74 is the minimum value of the function.

[tex]h=\dfrac{620}{x^2}\\\Rightarrow h=\dfrac{620}{10.74^2}\\\Rightarrow h=5.37[/tex]

So, minimum length and breadth of the box is 10.74 cm while the height of the box is 5.37 cm.

The total area of the sides is [tex]4xh=4\times 10.74\times 5.37=230.7\ \text{cm}^2[/tex]

The area of the base is [tex]x^2=10.74^2=115.35\ \text{cm}^2[/tex]

Cost of the base is $0.40 per square cm

Cost of the side is  $0.10 per square cm

Minimum cost would be

[tex]230.7\times 0.1+0.4\times 115.34=\$69.21[/tex]

The minimum cost of the box is 69.21 dollars.

Evaluate the surface integral


S
F · dS
for the given vector field F and the oriented surface S. In other words, find the flux of F across S. For closed surfaces, use the positive (outward) orientation.
F(x, y, z) = yj − zk,
S consists of the paraboloid
y = x2 + z2, 0 ≤ y ≤ 1,
and the disk
x2 + z2 ≤ 1, y = 1.

Answers

Since S is closed, you can use the divergence theorem, which says

[tex]\displaystyle\iint_S \vec F(x,y,z) \cdot \mathrm d\vec S=\iiint_R \mathrm{div}\vec F(x,y,z)\,\mathrm dV[/tex]

where R is the interior of the surface S.

We have

div F (x, y, z) = ∂/∂x (0) + ∂/∂y (y) + ∂/∂z (-z) = 1 - 1 = 0

so the flux would be 0.

In this exercise we have to calculate the flux by the divergent theorem:

The flux would be ZERO

Since S is closed, you can use the divergence theorem, which says:

[tex]\int\limits\int\limits_s {F(x,y,z} \, ds= \int\limits \int\limits\int\limits_R {divF(x, y, z)} \, dv[/tex]

where R is the interior of the surface S. We have:

[tex]\nabla F (x, y, z) = 1-1= 0[/tex]

so the flux would be ZERO.

See more about vectorial calculus at : brainly.com/question/6960786

The slipe of the line passing through the points (7, 5) and (21, 15) is

Answers

Answer:

5/7

Step-by-step explanation:

You find a slope by using the equation y2-y1/x2-x1.

In this case: 15-5/21-7

10/14

5/7

What is the slope of the line whose equation is y-6=2(x+3)?

Answers

Answer:

2

Step-by-step explanation:

y=mx+n m is slope

y-6=2(x+3) so y=2x+12  m=2 is slope.

7. Find the value of x and y:

x=

y=

(10x - 61)

(18y + 5)º

(x + 10)

Answers

Answer:

y = 8º

y = 8º  

Step-by-step explanation:

Given:

(10x - 61)º  

(18y + 5)º

(x + 10)º

Find:

x and y

Computation:

(10x - 61) + (x + 10) = 180

11x - 51 = 180

11x = 231

x = 21º

(10x - 61)º   = (18y + 5)º      [Vertical opposite angle]

10x - 61 = 18y + 5

10x - 18y = 66

5(21) - 9y = 33

y = 8º

! Find the slope using the formula.
(9,-5) and (-2,9)

Answers

Answer:

[tex]m=\frac{-14}{11}[/tex]

General Formula and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Algebra I

Slope Formula: [tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]

Step-by-step explanation:

Step 1: Define

Point (9, -5)

Point (-2, 9)

Step 2: Find slope m

Substitute:                    [tex]m=\frac{9+5}{-2-9}[/tex]Add/Subtract:               [tex]m=\frac{14}{-11}[/tex]Rewrite:                        [tex]m=\frac{-14}{11}[/tex]

The original price of a bottle
of dish soap is $2. How much
will Sasha PAY if she buys it
during the sale when it is 50%
off?

Answers

Answer:

$1

Step-by-step explanation:

i hope i read it right

Answer:

1

Step-by-step explanation:

cuz half of 2 is 1

Will spent $3.75 for 5 1/2 pounds of granola. What is his unit rate in dollars per pound to the nearest cent?

Answers

Answer:

Unitary cost (per pound)= $0.682

Step-by-step explanation:

Giving the following information:

Total cost= $3.75

Total pounds= 5.5 pounds

To calculate the unitary cost of each pound, we need to use the following formula:

Unitary cost= total cost / total pounds

Unitary cost per pound= 3.75 / 5.5

Unitary cost per pound= $0.682

(7w - 6) +5 (-2.4w + 1)

Answers

Answer: The answer would be -5w-1

Step-by-step explanation:

Answer:

xcgvb                     vgjbnnnnnnnnnn vbjn bvh

Step-by-step explanation:

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