y"+4y = 8 sin 2x. Trial Solution using annihilator technique
Linear Algebra and Differential equations
I am so confused why would you multiple by X up(x)

Answers

Answer 1

A second order linear, non - homogeneous ODE has a form of [tex]ay''+by'+cy=g(x)[/tex]

The general solution to, [tex]a(x)y''+b(x)y'+c(x)y=0[/tex]

Can be written as,

[tex]y=y_h+y_p[/tex]

Where [tex]y_h[/tex] is a solution to the homogeneous ODE and [tex]y_p[/tex] the particular solution, function that satisfies the non - homogeneous equation.

We can solve [tex]y_h[/tex] by rewriting the equation,

[tex]ay''+by'+cy=0\Longrightarrow(e^{xy})''+4e^{xy}=0[/tex]

Which simplifies to,

[tex]e^{xy}(y^2+4)=0[/tex]

From here we get two solutions,

[tex]y_{h1}=2i, y_{h2}=-2i[/tex]

So the form here refines,

[tex]y_h=c_1\cos(2x)+c_2\sin(2x)[/tex]

The same thing we do with [tex]y_p[/tex] to get form of,

[tex]y_p=-2x\cos(2x)[/tex]

From here the final form emerges,

[tex]y=\boxed{c_1\cos(2x)+c_2\sin(2x)-2x\cos(2x)}[/tex]

Hope this helps.

r3t40


Related Questions

Find the equation of the following line and graph. Through (3,-10) perpendicular to 5x-y=9

Answers

bearing in mind that perpendicular lines have negative reciprocal slopes, let's find the slope of 5x -  y = 9 then.

[tex]\bf 5x-y=9\implies -y=-5x+9\implies y=\stackrel{\stackrel{m}{\downarrow }}{5}x-9\leftarrow \begin{array}{|c|ll} \cline{1-1} slope-intercept~form\\ \cline{1-1} \\ y=\underset{y-intercept}{\stackrel{slope\qquad }{\stackrel{\downarrow }{m}x+\underset{\uparrow }{b}}} \\\\ \cline{1-1} \end{array} \\\\[-0.35em] ~\dotfill[/tex]

[tex]\bf \stackrel{\textit{perpendicular lines have \underline{negative reciprocal} slopes}} {\stackrel{slope}{5\implies \cfrac{5}{1}}\qquad \qquad \qquad \stackrel{reciprocal}{\cfrac{1}{5}}\qquad \stackrel{negative~reciprocal}{-\cfrac{1}{5}}}[/tex]

so then, we're really looking for the equation of a line whose slope is -1/5 and runs through (3,-10).

[tex]\bf (\stackrel{x_1}{3}~,~\stackrel{y_1}{-10})~\hspace{10em} slope = m\implies -\cfrac{1}{5} \\\\\\ \begin{array}{|c|ll} \cline{1-1} \textit{point-slope form}\\ \cline{1-1} \\ y-y_1=m(x-x_1) \\\\ \cline{1-1} \end{array}\implies y-(-10)=-\cfrac{1}{5}(x-3)\implies y+10=-\cfrac{1}{5}x+\cfrac{3}{5} \\\\\\ y=-\cfrac{1}{5}x+\cfrac{3}{5}-10\implies y=-\cfrac{1}{5}x+\cfrac{53}{5}[/tex]

and it looks like the one in the picture below.

Suppose that 15% of people dont show up for a flight, and suppose that their decisions are independent. how many tickets can you sell for a plane with 144 seats and be 99% sure that not too many people will show up.

The book says to do this by using the normal distribution function and that the answer is selling 157 tickets.

Answers

Answer: 157 tickets

Explanation:

The people not showing up for the flight can be treated as from Binomial distribution.

The binomial distribution B(n, p) is approximately close to the normal i.e. N(np, np(1 − p))  for large 'n' and for 'p' and neither too close to 0 nor 1 .

Now, Let us assume 'n' = n

and we are given

p=0.15

So now B(n,0.15n) follows Normal distribution

u=n

[tex]\sigma^{2}[/tex] = 0.15n

We have to calculate P(X<144) with 99% accuracy

P(X<144) = P(Z<z)

where;

z= [tex](144-\bar{X})\div \sigma[/tex]

z score for 99% is 2.33

i.e.  

[tex](144-\bar{X})\div \sigma = (144-n)/\sqrt{np} = 2.33\\\ (144-n)^{2} = \ np*2.33^{2}\\\ 20736 +n^{2} - 288n = 0.15n*5.43\\\ n^{2} - 288.81n + 20736=0[/tex]

solving this we will get one root nearly equal to 157 and other root as 133

Hence the answer is 157.

Several years​ ago, the mean height of women 20 years of age or older was 63.7 inches. Suppose that a random sample of 45 women who are 20 years of age or older today results in a mean height of 65.1 inches. ​(a) State the appropriate null and alternative hypotheses to assess whether women are taller today. ​(b) Suppose the​ P-value for this test is 0.16. Explain what this value represents. ​(c) Write a conclusion for this hypothesis test assuming an alphaequals0.10 level of significance.

Answers

Answer:

​(a) State the appropriate null and alternative hypotheses to assess whether women are taller today.

Solution:

Definition of null hypothesis : The null hypothesis attempts to show that no variation exists between variables or that a single variable is no different than its mean. it is denoted

Alternative Hypothesis: In statistical hypothesis testing, the alternative hypothesis is a position that states something is happening, a new theory is true instead of an old one (null hypothesis).

We are given that The mean height of women 20 years of age or older was 63.7 inches.

So, null hypothesis : [tex]H_0: \mu=63.7[/tex]

Alternative Hypothesis : [tex]H_1: \mu>63.7[/tex]

b)The​ P-value for this test is 0.16.

Solution: The p-value represents the probability of getting a sample mean height of 65.1 inches.

c) Write a conclusion for this hypothesis test assuming an alpha equals 0.10 level of significance.

Solution:

[tex]\alpha = 0.10[/tex]

p- value = 0.16

[tex]p-value> \apha[/tex]

Since the p - value is high .

So, we will accept the null hypothesis

So,  [tex]H_0: \mu=63.7[/tex]

Hence The mean height is 63.7 inches

Final answer:

The null hypothesis states that the mean height of women today is equal to the mean height several years ago. The P-value represents the probability of obtaining the observed sample mean if the null hypothesis is true. With an alpha level of 0.10, we fail to reject the null hypothesis, indicating no significant evidence to suggest that women today are taller.

Explanation:

(a) Null hypothesis: The mean height of women 20 years of age or older today is equal to 63.7 inches. Alternative hypothesis: The mean height of women 20 years of age or older today is greater than 63.7 inches.

(b) The P-value represents the probability of obtaining a sample mean height of 65.1 inches or higher, given that the true mean height is 63.7 inches. A P-value of 0.16 indicates that there is a 16% chance of observing such a sample mean height even if the true mean height is 63.7 inches.

(c) Conclusion: Assuming an alpha level of 0.10, we fail to reject the null hypothesis. There is not enough evidence to conclude that women today are taller than before.

Learn more about Hypothesis testing here:

https://brainly.com/question/34171008

#SPJ3

3. Find the inverse Laplace transform of F(s) = (-4s-9) / (s^2 + 25-8) f(t) =

Answers

[tex]f(s)\Longrightarrow L^{-1}=\{\frac{-4s-9}{s^2+25-8}\}[/tex]

First dismantle,

[tex]L^{-1}=\{-\frac{4s}{s^2+25-8}-\frac{9}{s^2+25-8}\}[/tex]

Now use the linearity property of Inverse Laplace Transform which states,

For functions [tex]f(s),g(s)[/tex] and constants [tex]a, b[/tex] rule applies,

[tex]L^{-1}=\{a\cdot f(s)+b\cdot g(s)\}=aL^{-1}\{f(s)\}+bL^{-1}\{f(s)\}[/tex]

Hence,

[tex]-4L^{-1}\{\frac{s}{s^2+25-8}\}-9L^{-1}\{\frac{1}{s^2+25-8}\}[/tex]

The first part simplifies to,

[tex]

L^{-1}\{\frac{s}{s^2+25-8}\} \\

\frac{d}{dt}(\frac{1}{\sqrt{17}}\sin(t\sqrt{17})) \\

\cos(t\sqrt{17})

[/tex]

The second part simplifies to,

[tex]

L^{-1}\{\frac{1}{s^2+25-8}\} \\

\frac{1}{\sqrt{17}}\sin(t\sqrt{17})

[/tex]

And we result with,

[tex]\boxed{-4\cos(t\sqrt{17})-\frac{9}{\sqrt{17}}\sin(t\sqrt{17})}[/tex]

Hope this helps.

If you have any additional questions please ask. I made process of solving as quick as possible therefore you might be left over with some uncertainty.

Hope this helps.

r3t40

4.D.15 Consider a student loan of $17,500 at a fixed APR of 6% for 25 years. a. Calculate the monthly payment. b. Determine the total amount paid over the term of the loan. c. Of the total amount paid, what percentage is paid toward the principal and what percentage is paid for interest a. The monthly payment is $ (Do not round until the final answer. Then round to the nearest cent as needed.) ess ibrary

Answers

Final answer:

The monthly payment for a $17,500 loan at 6% APR over 25 years is about $113.36. The total amount paid over the duration of the loan is $34,008, of which about 51.46% goes towards the principal and 48.54% towards interest.

Explanation:

To answer this question, we need to use the formula for calculating the monthly payment for a loan, which is P[r(1 + r)^n]/[(1 + r)^n - 1], where P is the principal loan amount, r is the monthly interest rate (annual rate divided by 12), and n is the number of payments (years times 12).

a. Monthly payment:

First, we have to calculate r: 6% APR implies a yearly interest rate of 6%/12 = 0.005 per month. Plugging P = $17,500, r = 0.005, and n = 25*12 = 300 into the formula, we get the monthly payment of approximately $113.36.

b. Total amount paid:

The total amount paid over the duration of the loan is simply the monthly payment times the total number of payments, so $113.36*300 = $34,008.

c. Percentages of principal and interest:

The percentage paid towards the principal is the original loan amount divided by the total payment amount times 100, so $17,500/$34,008*100 = approximately 51.46%. Therefore, the percentage paid for interest is 100 - 51.46 = 48.54%.

Learn more about Student Loan here:

https://brainly.com/question/32329996

#SPJ3

The monthly payment for the loan is approximately $114.08. Over 25 years, the total amount paid will be about $34,224. About 51.11% of this amount goes toward the principal and 48.89% goes toward interest.

To solve this problem, we need to calculate the monthly payment, total amount paid, and the percentages of principal and interest paid for a student loan of $17,500 at a fixed APR of 6% for 25 years.

a. Calculate the monthly payment

We use the formula for the monthly payment on an amortizing loan:

→ [tex]M = P [r(1 + r)^n] / [(1 + r)^{n - 1}][/tex]

where:

→ P = loan principal ($17,500)

→ r = monthly interest rate (annual rate / 12)

    = 6% / 12

    = 0.005

→ n = total number of payments (years * 12)

     = 25 * 12

     = 300

Substituting the values into the formula:

→ [tex]M = 17500 [0.005(1 + 0.005)^{300}] / [(1 + 0.005)^{300 – 1}][/tex]

→ M = 17500 [0.005(4.2918707)] / [4.2918707 – 1]

→ M = 17500 [0.02145935] / [3.2918707]

→ M = 375.53965 / 3.2918707

→ M ≈ $114.08

b. Determine the total amount paid over the term of the loan

→ Total amount paid = monthly payment * total number of payments

→ Total amount paid = 114.08 * 300

                                 ≈ $34,224

c. Of the total amount paid, what percentage is paid toward the principal and what percentage is paid for interest

→ Principal: $17,500

→ Interest: Total amount paid - Principal

→ Interest = 34,224 - 17,500

                ≈ $16,724

→ Percentage toward principal = (Principal / Total amount paid) * 100

                                                   ≈ (17500 / 34224) * 100

                                                   ≈ 51.11%

→ Percentage toward interest = (Interest / Total amount paid) * 100

                                                 ≈ (16724 / 34224) * 100

                                                 ≈ 48.89%

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) = −xi − yj + z3k, S is the part of the cone z = x2 + y2 between the planes z = 1 and z = 2 with downward orientation.

Answers

The equation of the cone should be [tex]z=\sqrt{x^2+y^2}[/tex]. Parameterize [tex]S[/tex] by

[tex]\vec s(u,v)=u\cos v\,\vec\imath+u\sin v\,\vec\jmath+u\,\vec k[/tex]

with [tex]1\le u\le2[/tex] and [tex]0\le v\le2\pi[/tex]. Take the normal vector to [tex]S[/tex] to be

[tex]\vec s_v\times\vec s_u=u\cos v\,\vec\imath+u\sin v\,\vec\jmath-u\,\vec k[/tex]

Then the integral of [tex]\vec F[/tex] across [tex]S[/tex] is

[tex]\displaystyle\iint_S\vec F\cdot\mathrm d\vec S=\int_0^{2\pi}\int_1^2(-u\cos v\,\vec\imath-u\sin v\,\vec\jmath+u^3\,\vec k)\cdot(u\cos v\,\vec\imath+u\sin v\,\vec\jmath-u\,\vec k)\,\mathrm du\,\mathrm dv[/tex]

[tex]=\displaystyle\int_0^{2\pi}\int_1^2(-u^2-u^4)\,\mathrm du\,\mathrm dv[/tex]

[tex]=\displaystyle-2\pi\int_1^2(u^2+u^4)\,\mathrm du\,\mathrm dv=\boxed{-\frac{256\pi}{15}}[/tex]

Final answer:

To evaluate the surface integral, we need to find the flux of the vector field F across the oriented surface S. Given that F(x, y, z) = −xi − yj + z3k, and S is the part of the cone z = x2 + y2 between the planes z = 1 and z = 2 with downward orientation, we can proceed as follows: First, find the unit normal vector to the surface. Next, calculate the dot product between the vector field F and the unit normal vector. Finally, integrate the dot product over the surface S using the downward orientation.

Explanation:

To evaluate the surface integral, we need to find the flux of the vector field F across the oriented surface S. Given that F(x, y, z) = −xi − yj + z3k, and S is the part of the cone z = x2 + y2 between the planes z = 1 and z = 2 with downward orientation, we can proceed as follows:

First, we need to find the unit normal vector to the surface. In this case, the unit normal vector is -∇(z - x^2 - y^2)/|∇(z - x^2 - y^2)|. By calculating the gradient and normalizing it, we get the unit normal vector as (2x, 2y, -1)/√(1 + 4x^2 + 4y^2).Next, we calculate the dot product between the vector field F and the unit normal vector. The dot product is -2x - 2y + z^3.Finally, we integrate the dot product over the surface S using the downward orientation. The integral is given by ∫∫S (-2x - 2y + z^3)dS.

Learn more about Surface Integral here:

https://brainly.com/question/32088117

#SPJ3

Two cards are drawn without replacement from a standard deck of 52 playing cards. What is the probability of choosing a red card for the second card drawn, if the first card, drawn without replacement, was a diamond? Express your answer as a fraction or a decimal number rounded to four decimal places.

Answers

Final answer:

If the first card drawn is a diamond, the total number of cards reduces to 51 for the second draw. Out of these, 25 are red (13 hearts + 12 diamonds). So, the probability of drawing a red card on the second draw, if the first drawn card was a diamond, is 25/51 approximated to 0.4902.

Explanation:

The subject of this question is probability in mathematics, specifically related to a scenario that involves sampling without replacement from a deck of playing cards. Firstly, let us familiarize ourselves with the composition of a standard deck of cards. It consists of 52 cards divided into four suits: clubs, diamonds, hearts, and spades. Clubs and spades are black cards, while diamonds and hearts are red cards. Each suit has 13 cards.

If the first card drawn is a diamond, the total count of cards in the deck reduces to 51 (because we are drawing without replacement), and, since a diamond card has been withdrawn, the count of remaining red cards is 25 (13 hearts and 12 remaining diamonds). Thus, to find the probability of drawing a red card on the second draw, we simply count the remaining red cards and divide by the remaining total cards, giving us a probability of 25/51 or approximately 0.4902 when rounded to four decimal places.

Learn more about Probability here:

https://brainly.com/question/32117953

#SPJ12

The probability of choosing a red card for the second card drawn, if the first card was a diamond, is 0.4902.

Determine the total number of cards in a standard deck: A standard deck has 52 cards in total.

Count the diamonds in the deck: There are 13 diamonds in the deck.

Calculate the probability of drawing a diamond first: The probability is the number of diamonds over the total number of cards.
  [tex]\[ \text{Probability of drawing a diamond first} = \frac{13}{52} = 0.25 \][/tex]

Update the deck after drawing the first card: After drawing a diamond, there are now 51 cards left in the deck and one less red card.

Count the red cards left in the deck: A standard deck has 26 red cards (13 diamonds and 13 hearts). After drawing one diamond, there are 25 red cards remaining.

Calculate the probability of drawing a red card second, given that the first card was a diamond: The probability of this happening is the number of remaining red cards over the remaining number of cards in the deck.
  [tex]\[ \text{Probability of drawing a red card second} = \frac{25}{51} \approx 0.4902 \][/tex]

So, the calculated probabilities are:

- The probability of drawing a diamond first: 0.25
- The probability of drawing a red card second, given that the first card drawn was a diamond: 0.4902

Therefore, the probability of choosing a red card for the second card drawn, if the first card was a diamond, is approximately 0.4902.

If you are asked to provide a set of two or more numeric answers, separate them with commas. For example, to provide the year that Sputnik (the first satellite to be sent into orbit around the Earth) was launched and the year humans first walked on the Moon, you would enter 1957,1969 in the answer box.A rectangle has a length of 5.50 m and a width of 12.0 m. What are the perimeter and area of this rectangle?Enter the perimeter and area numerically separated by a comma. The perimeter should be given in meters and the area in square meters. Do not enter the units; they are provided to the right of the answer box.

Answers

Answer:

  35, 66

Step-by-step explanation:

The perimeter is twice the sum of length and width:

  2(5.50 m + 12.0 m) = 2(17.50 m) = 35.00 m

__

The area is the product of the length and width:

  (5.50 m)(12.0 m) = 66.000 m^2

Final answer:

The perimeter of the rectangle is 35.0 m, and the area is 66.0 m², both calculated using standard geometry formulas and reported with three significant figures.

Explanation:

To calculate the perimeter and area of a rectangle, we use the formulas: Perimeter = 2(length + width) and Area = length × width. In this case, the rectangle has a length of 5.50 m and a width of 12.0 m. Therefore, the perimeter is 2(5.50 m + 12.0 m) = 2(17.5 m) = 35.0 m. The area is 5.50 m × 12.0 m = 66.0 m².

It's important to express your answers with the correct number of significant figures and proper units. The length of 5.50 m has three significant figures, and the width of 12.0 m has three significant figures as well. Thus, our final answers for both perimeter and area should also be reported to three significant figures: 35.0 m for the perimeter and 66.0 m² for the area.


I need the answer to this question.

1) Divide 704 days 11 hours by 29.

Answers

There are 24 hours to a day, so you can write this as

704 days, 11 hours = 704 + 11/24 days

Then dividing by 29 gives

704/29 + 11/696 days

We have

704 = 24*29 + 8

so that the time is equal to

24 + 8/29 + 11/696 days

24 + (192 + 11)/696 days

24 + 7/24 days

which in terms of days and hours is

24 days, 7 hours

You have $500,000 saved for retirement. Your account earns 4% interest. How much will you be able to pull out each month, if you want to be able to take withdrawals for 25 years?

Answers

Answer:

amount pull out each month is $4518.44

Step-by-step explanation:

principal (p) = $500000

rate (r) = 4% = 0.04 = 0.04/12 per month

time period = 25 years = 25 × 12 = 300 months

to find out

how much amount pull out each month

solution

we will calculate the amount by given formula i.e.

principal = amount  ( 1 - [tex](1+r)^{t}[/tex] ) / r     ....................1

now put the value amount rate time in equation 1

we get amount

500000 = amount ( 1 - [tex](1+0.04/12)^{300}[/tex] ) / 0.04/12

500000 = amount (2.711062 ) / 0.00333

amount = 1666.6666 * 2.711062

amount =  4518.44

amount pull out each month is $4518.44

Final answer:

To determine how much you can pull out each month, you can use the formula for the future value of an ordinary annuity. Plugging in the given values, you will be able to pull out approximately $1,408.19 each month if you want to be able to take withdrawals for 25 years.

Explanation:

To determine how much you can pull out each month, you can use the formula for the future value of an ordinary annuity. The formula is:

FV = P * [(1 + r)^n - 1] / r

Where:

FV is the future value of the annuity

P is the monthly withdrawal amount

r is the monthly interest rate (4% divided by 12)

n is the number of months (25 years multiplied by 12)

Plugging in the values, we get:

FV = P * [(1 + 0.04/12)^(25*12) - 1] / (0.04/12)

To find the monthly withdrawal amount (P), we need to solve for P. Rearranging the formula:

P = FV * (0.04/12) / [(1 + 0.04/12)^(25*12) - 1]

Now substitute the values back in and calculate P:

P = $500,000 * (0.04/12) / [(1 + 0.04/12)^(25*12) - 1]

Simplifying the equation gives us:

P ≈ $1,408.19

Therefore, you will be able to pull out approximately $1,408.19 each month if you want to be able to take withdrawals for 25 years.

By convention, the independent variable is arrayed along the ____ in a scattergram. regression line calibration line vertical axis (the ordinate) horizontal axis (the abscissa)

Answers

Answer:

Horizontal axis

Step-by-step explanation:

By convention, the independent variables is arrayed along the Horizontal axis (abscissa) in a scattergram.

The stcattergram has two dimensions

The X (independent) variable is arrayed along the horizontal axis.The Y(dependent) variable is arrayed along the vertical axis.Each dot scattergram is case in data set.The dot is placed at the intersection cases scores on X and Y.

.3 3. True or False? For any integer m, 2m(3m + 2) is divisible by 4. Explain to get credit.

Answers

Answer with explanation:

We have to prove that, For any integer m, 2 m×(3 m + 2) is divisible by 4.

We will prove this result with the help of Mathematical Induction.

⇒For Positive Integers

For, m=1

L HS=2×1×(3×1+2)

      =2×(5)

       =10

It is not divisible by 4.

⇒For Negative Integers

For, m= -1

L HS=2×(-1)×[3×(-1)+2]

      =-2×(-3+2)

       = (-2)× (-1)

       =2

It is not divisible by 4.

False Statement.

Consider the region satisfying the inequalities.y ≤ e−x, y ≥ 0, x ≥ 0a) Find area of regionb) Find the volume of the solid generated by revolving the region about the x-axis.c) Find the volume of the solid generated by revolving the region about the y-axis.

Answers

Revolving about the [tex]x[/tex]-axis:

Using the disk method, the volume is

[tex]\displaystyle\pi\int_0^\infty e^{-2x}\,\mathrm dx=\boxed{\frac\pi2}[/tex]

Alternatively, using the shell method, the volume is

[tex]\displaystyle2\pi\int_0^1y(-\ln y)\,\mathrm dy=\frac\pi2[/tex]

Revolving about the [tex]y[/tex]-axis:

Using the shell method, the volume is

[tex]\displaystyle2\pi\int_0^\infty xe^{-x}\,\mathrm dx=\boxed{2\pi}[/tex]

Alternatively, using the disk method, the volume is

[tex]\displaystyle\pi\int_0^1(-\ln x)^2\,\mathrm dx=2\pi[/tex]

Final answer:

The area of the region is 1 square unit. The volume of the solid generated by revolving the region about the x-axis can be found by integrating π(y^2) dx from x = 0 to x = ∞.

Explanation:

To find the area of the region, we need to find the intersection points between the two curves. In this case, the curves are y = e^(-x) and y = 0. Since y ≥ 0, the region will lie between the x-axis and the curve y = e^(-x). The intersection point is where y = 0, which occurs at x = 0. To find the area, we integrate y = e^(-x) from x = 0 to x = ∞:

A = ∫0∞ e^(-x) dx = [-e^(-x)]0∞ = -[e^0 - 0]
               = -[1 - 0] = 1

The area of the region is 1 square unit.

To find the volume of the solid generated by revolving the region about the x-axis, we use the disk method. The radius of each disk is given by y = e^(-x), and the height of each disk is given by dx. The volume can be found by integrating π(y^2) dx from x = 0 to x = ∞:

V = π∫0∞ (e^(-x))^2 dx = π∫0∞ e^(-2x) dx

Find the fixed points of f(x) = 2x - x3 and determine their stability.

Answers

Answer with explanation:

⇒ A point k is said to be fixed point of function, f(x) if

        f(k)=k.

The given function is

           f(x)=2 x - x³

To determine the fixed point

f(k)=2 k - k³=k

→2 k -k -k³=0

→k -k³=0

→k×(1-k²)=0

→k(k+1)(k-1)=0

→k=0 ∧ k+1=0∧k-1=0

→k=0∧ k= -1 ∧ k=1

So, the three fixed points are=0,1 and -1.

To Check Stability of fixed point

1.⇒  f'(x)=2-3 x²

|f'(0)|=|2×0-0³|=0

⇒x=0, is Superstable point.

2.⇒|f'(-1)|=2 -3×(-1)²

 =2 -3

= -1

|f'(-1)| <1

⇒x= -1, is stable point.

3.⇒|f'(1)|=2 -3×(1)²

=2 -3

= -1

|f'(1)| <1

⇒x= 1, is also a stable point.

⇒⇒There are two points of Stability,which are, x=1 and , x=-1.

Suppose consumers will demand 40 units of a product when the price is $12 per unit and 25 units when the price is $18 each. Find the demand equation assuming that it is linear. Find the price per unit when 30 units are demanded.

Answers

Answer: The price per unit is $48, when 30 units are demanded.

Step-by-step explanation:

Since we have given that

At price of $12 per unit, the number of units demanded = 40 units

At price of $18 per unit, the number of units demanded = 25 units.

So, the coordinates would be

(40,12) and (25,18)

As we know that x- axis denoted the quantity demanded.

y-axis denoted the price per unit.

So, the slope would be

[tex]m=\dfrac{y_2-y_1}{x_2-x_1}\\\\m=\dfrac{18-12}{25-40}\\\\m=\dfrac{-6}{15}\\\\m=\dfrac{-2}{5}[/tex]

So, the equation would be

[tex]y-y_1=m(x-x_1)\\\\y-12=\dfrac{-2}{5}(x-40)\\\\5(y-12)=-2(x-40)\\\\5y-60=-2x+80\\\\5y+2x=80+60\\\\5y+2x=140[/tex]

So, if 30 units are demanded, the price per unit would be

[tex]5y=140+2x\\\\5y=140+2\times 30\\\\5y=140+60\\\\5y=240\\\\y=\dfrac{240}{5}\\\\y=\$48[/tex]

Hence, the price per unit is $48, when 30 units are demanded.

Final answer:

The linear demand equation is Qd = 100 - 5P. In this equation, if we want to find the price per unit when 30 units are demanded, substitute Qd with 30 to get P = 14.

Explanation:

To find the linear demand equation, we can use the data given: consumers will buy 40 units of a product when the price is $12 per unit and 25 units when the price is $18 per unit. The general formula for a linear demand equation is Qd = a - bP, where Qd is the quantity demanded, P is the price per unit, a is the intercept, and b is the slope of the demand curve.

Let's use the two points (12, 40) and (18, 25) to formulate two equations with a and b as unknowns. We find that a = 100 and b = 5, therefore the demand equation is Qd = 100 - 5P. Now if we want to find the price per unit when 30 units are demanded, we just need to substitute Qd with 30 in the demand equation, hence P = 14.

Learn more about Demand Equation here:

https://brainly.com/question/34102394

#SPJ3

PLEASE HELP PRECALCULUS WILL MARK BRAINLIEST -SEE ATTACHMENT-

Answers

Answer:

Maximum is 8 while the minimum is -8.

Step-by-step explanation:

If we consider y=cos(x), the maximum is 1 and the minimum is -1.

This is the parent function of y=8cos(x) which has been vertically stretched by a factor of 8.  So now the maximum of y=8cos(x) is 8 while the minimum of y=8cos(x) is -8.

How many 3 digit pass codes can be made from the digits 0 to 9 if the first number is not allowed to be a 0?

Answers

Answer:

total 900 pass codes can be made.

Step-by-step explanation:

Given situation is 3 digit pass codes are required made from the digits 0 to 9.

But the first number is not allowed to be a 0.

So for the third place we have 10 choices ( 0,1,2,3,4,5,6,7,8,9 )

For the second place we have 10 choices ( 0,1,2,3,4,5,6,7,8,9 )

But for the first place we have 9 choices ( 1,2,3,4,5,6,7,8,9 )

( 9 × 10 × 10 ) = 900

Therefore, total 900 pass codes can be made from the digits 0 to 9.


Samâs Auto Shop services and repairs a particular brand of foreign automobile. Sam uses oil filters throughout the year. The shop operates fifty-two weeks per year and weekly demand is 150 filters. Sam estimates that it costs $20 to place an order and his annual holding cost rate is $3 per oil filter. Currently, Sam orders in quantities of 650 filters. Calculate the total annual costs associated with Samâs current ordering policy

Total annual costs = $

Answers

the total annual costs associated with Sam's current ordering policy amount to $1,215.

The student has provided the necessary information to calculate the total annual costs associated with Sam's current ordering policy at his auto shop. Sam orders 650 oil filters at a time and the shop uses 150 filters per week. The key components involved in this calculation are the order cost, annual demand, holding cost, and the size of each order.

Total Annual Costs Calculation

The total annual demand (D) is the weekly demand (d) multiplied by the number of weeks per year:

D = d × 52
D = 150 filters/week × 52 weeks/year
D = 7,800 filters/year

The order cost (S) is given as $20 per order and the annual holding cost per unit (H) is $3 per filter. The size of each order (Q) is 650 filters.

The total annual ordering cost (AOC) can be calculated as the annual demand divided by the order size, multiplied by the order cost:

AOC = (D/Q)  × S
AOC = (7,800/650) × $20
AOC = 12 × $20
AOC = $240

The total annual holding cost (AHC) can be calculated as the average inventory level (which is Q/2 for consistent orders) multiplied by the holding cost per unit:

AHC = (Q/2) × H
AHC = (650/2) × $3
AHC = 325 × $3
AHC = $975

The total annual costs (TAC) are the sum of the total annual ordering cost and the total annual holding cost:

TAC = AOC + AHC
TAC = $240 + $975
TAC = $1,215

Therefore, the total annual costs associated with Sam's current ordering policy amount to $1,215.

PLEASE HELP PRECALCULUS WILL MARK BRAINLIEST

Answers

Answer:

[tex]\dfrac{21\pi}{10},\ -\dfrac{19\pi}{10}[/tex]

Step-by-step explanation:

Any of the angles (in radians) π/10 +2kπ (k any integer) will be co-terminal with π/10. The angles listed in the answer above have k=1, k=-1.

_____

Comment on the last answer choice

The answer choices π/10+360° and π/10-360° amount to the same thing as the answer shown above, but use mixed measures. 1 degree is π/180 radians, so 360° is 2π radians. Then π/10+360° is fully equivalent to 21π/10 radians.

divide

(3x^2 + 9x + 7) divide by (x+2)

Answers

Answer:

The remainder is: 3x+3

The quotient is: 1

Step-by-step explanation:

We need to divide

(3x^2 + 9x + 7) by (x+2)

The remainder is: 3x+3

The quotient is: 1

The solution is attached in the figure below.

Answer:

[tex]3x+3+\frac{1}{x+2}[/tex]

Step-by-step explanation:

We are to divide the polynomial [tex]3x^2 + 9x + 7[/tex] by [tex]x+2[/tex].

For that, we will first divide the leading coefficient of the numerator [tex]\frac{3x^2}{x}[/tex] by the divisor.

So we get the quotient: [tex]3x[/tex] and will multiply the divisor [tex]x+2[/tex] by [tex]3x[/tex] to get [tex]3x^2+6x[/tex].

Next, we will subtract [tex]3x^2+6x[/tex] from [tex]3x^2 + 9x + 7[/tex] to get the remainder [tex]3x+7[/tex].

Therefore, we get [tex]3x+\frac{3x+7}{x+2}[/tex].

Now again, dividing the leading coefficient of the numerator by the divisor [tex]\frac{3x}{x}[/tex] to get quotient [tex]3[/tex].

Then we will multiply [tex]x+2[/tex] by [tex]3[/tex] to get [tex]3x+6[/tex].

Then, we will subtract [tex]3x+6[/tex] from [tex]3x+7[/tex] to get the new remainder [tex]1[/tex].

Therefore, [tex]\frac{3x^2 + 9x + 7}{x+2}=3x+3+\frac{1}{x+2}[/tex]

Use the method of cylindrical shells to find the volume V generated by rotating the region bounded by the given curves about the specified axis. y = x3, y = 8, x = 0; about x = 9

Answers

Answer:

200π cubic units.

Step-by-step explanation:

Use the general method of integrating the area of the surface  generated by an arbitrary cross section of the region  taken parallel to the axis of revolution.

Here the axis  x = 9 is parallel to the y-axis.

The height of  one cylindrical shell = 8 - x^3.

The radius = 9 - x.

                                               2

The volume generated =  2π∫   (8 - x^3) (9 - x) dx

                                               0

= 2π ∫ ( 72 - 8x - 9x^3 + x^4) dx

             2

=      2 π [    72x - 4x^2 - 9x^4/4 + x^5 / 4  ]

            0

= 2 π  ( 144 - 16  - 144/4 + 32/4)

= 2 π * 100

= 200π.

An instructor at a major research university occasionally teaches summer session and notices that that there are often students repeating the class. Out of curiosity, she designs a random sample of students enrolled in summer sessions and counts the number repeating a class. She counts 105 students in the sample, of which 19 are repeating the class. She decides a confidence interval provides a good estimate of the proportion of students repeating a class. She wants a 95% confidence interval with a margin of error at most ????=0.025m=0.025 . She has no idea what the true proportion could be. How large a sample should she take? 250 1537 1500 400

Answers

Answer: 1537

Step-by-step explanation:

Given : Margin of error : [tex]E=0.025[/tex]

Significance level : [tex]\alpha=1-0.95=0.05[/tex]

Critical value : [tex]z_{\alpha/2}=z_{0.025}=1.96[/tex]

The formula to calculate the sample size if prior estimate pf population proportion does not exist :-

[tex]n=0.25(\dfrac{z_{\alpha/2}}{E})^2\\\\\Rightarrow\ n=0.25(\dfrac{1.96}{0.025})^2\\\\\Rightarrow\ n=1536.64\approx1537[/tex]

Hence, she should take a sample with minimum size of 1537 .

Final answer:

To estimate the proportion of students repeating a class with a 95% confidence level and a margin of error of 0.025, the instructor would need a sample size of at least 1537 students.

Explanation:

To calculate the sample size needed for constructing a 95% confidence interval for the proportion of students who are repeating a class with a specified margin of error, we can use the formula for sample size in a proportion:

n = (Z² × p × (1-p)) / E²

Where:

Z is the Z-value from the standard normal distribution corresponding to the desired confidence level (for a 95% confidence interval, Z is approximately 1.96).p is the estimated proportion of success (in this case, we use a conservative estimate of 0.5, per the instructor's uncertainty).E is the desired margin of error (0.025 in this case).

Substituting the values, we get:

Z = 1.96p = 0.5 (as the instructor has no idea about the true proportion)E = 0.025

Thus, the calculation is:

n = (1.96² × 0.5 × (1 - 0.5)) / 0.025²

n = (3.8416 × 0.25) / 0.000625

n = 0.9604 / 0.000625

n = 1536.64

As we cannot have a fraction of a person, we would round up to the next whole number.

Therefore, the instructor would need to sample at least 1537 students.

\sum_{n=1}^{\infty } ((-1^n)/n)x^n

Find the interval of convergence.

Answers

Answer:

(-1,1).

Step-by-step explanation:

We need to calculate [tex]\lim_{n \to \infty}\frac{| a_{n+1}|}{| a_{n}|} = \frac{1}{R}[/tex] where R is the radius of convergence.

[tex]\lim_{n \to \infty}\frac{\frac{|(-1)^{n+1}|}{|n+1|}}{\frac{|(-1)^{n}|}{|n|}}[/tex]

[tex]\lim_{n \to \infty}\frac{\frac{1}{|n+1|}}{\frac{1}{|n|}}[/tex]

[tex]\lim_{n \to \infty}\frac{|n|}{|n+1|}[/tex]

Applying LHopital rule we obtaing that the limit is 1. So [tex]1=\frac{1}{R}[/tex] then R = 1.

As the serie is the form [tex](x+0)^{n}[/tex] we center the interval in 0. So the interval is (0-1,0+1) = (-1,1). We don't include the extrem values -1 and 1 because in those values the serie diverges.

27-28 . Find the acute angles between the curves at their points of intersection. (The angle between two curves is the angle between their tangent lines at the point of intersection. 27. y = x, y = x 28. y = sinx, y = cos x, 0

Answers

Answer:

27.The angle between two given curves is [tex]0^{\circ}[/tex].

28.[tex]\theta=tan^{-1}(2\sqrt2)[/tex]

Step-by-step explanation:

27.We are given that two curves

y=x,y=x

We have to find the angle between the two curves

The angle between two curves is the angle between their tangent lines at the point of intersection

We know that the values of both curves at the point of intersection are equal

Let two given curves intersect at point [tex](x_1,y_1)[/tex]

Then [tex]y_1=x_1[/tex] because both curves are same

[tex]\frac{dy}{dx}=1[/tex]

[tex]m_1=1,m_2=1[/tex]

[tex]m_1(x_1)=1,m_2(x_1)=1[/tex]

Using formula of angle between two curves

[tex]tan\theta=\frac{m_1(x_0)-m_2(x_0)}{1+m_1(x_0)m_2(x_0)}[/tex]

[tex]tan\theta=\frac{1-1}{1+1}=\frac{0}{2}=0[/tex]

[tex]tan\theta=tan 0^{\circ}[/tex]

[tex]\theta=0^{\circ}[/tex]

Hence,the angle between two given curves is [tex]0^{\circ}[/tex].

28.y=sin x

y= cos x

By similar method we solve these two curves

Let two given curves intersect at point (x,y) then the values of both curves at the point are equal

Therefore,  sin x = cos x

[tex]\frac{sin x}{cos x}=1[/tex]

[tex]tan x=1[/tex]

[tex]tan x=\frac{sin x}{cos x}[/tex]

[tex]tan x= tan \frac{\pi}{4}[/tex]

[tex]x=\frac{\pi}{4}[/tex]

Now, substitute the value of x then we get y

[tex]y= sin \frac{\pi}{4}=\frac{1}{\sqrt2}[/tex]

[tex] sin \frac{\pi}{4}=cos \frac{\pi}{4}=\frac{1}{\sqrt2}[/tex]

The values of both curves are same therefore, the point [tex](\frac{\pi}{4},\frac{1}{\sqrt2})[/tex] is the intersection point of two curves .

[tex]m_1=cos x[/tex]

At [tex] x=\frac{\pi}{4}[/tex]

[tex]m_1=\frac{1}{\sqrt2}[/tex]

and

[tex]m_2=-sin x=-\frac{1}{\sqrt2}[/tex]

Substitute the values in the above given formula

Then we get [tex]tan\theta =\frac{\frac{1}{\sqrt2}+\frac{1}{\sqrt2}}{1-\frac{1}{2}}[/tex]

[tex]tan\theta=\frac{\frac{2}{\sqrt 2}}{\frac{1}{2}}[/tex]

[tex]tan\theta=\frac{2}{\sqrt 2}\times 2[/tex]

[tex] tan\theta=\frac{4}{\sqrt2}=\frac{4}{\sqrt 2}\times\frac{\sqrt2}{\sqrt2}[/tex]

[tex]tan\theta=2\sqrt2[/tex]

[tex]\theta=tan^{-1}(2\sqrt2)[/tex]

Hence, the angle between two curves is [tex]tan^{-1}(2\sqrt2)[/tex].

define the variables, write a system if equations corresponding to the problem, and solve the problem. 2. A group of four golfers pays $150 to play a round of golf. Of these four, one is a member of the club and three are nonmembers. Another group of golfers consists of two members and one nonmember and pays a total of $75. What is the cost for a member to play a round of golf, and what is the cost for a nonmember?

Answers

Answer: Cost of member = $15 and Cost of non member = $45

Step-by-step explanation:

a) Define variables.

Let x be the cost of member.

Let y be the cost of non member.

b) Write a system of equations:

According to question, we get that

x+3y=$150--------------(1)

2x+y=$75---------------(2)

Now, we need to calculate the cost for a member and a non member.

Using graphing method, we get that (15,45) is the solution set.

Hence, cost of member = $15 and Cost of non member = $45

PLEASE HELP PRECALCULUS WILL MARK BRAINLIEST
see attachment'

Answers

Check the picture below.

Answer:

2

Step-by-step explanation:

Kristie has taken five tests in science class. The average of all five of Kristie's test scores is 94. The average of her last three test scores is 92. What is the average of her first two test scores?

Answers

Answer:  The average of the first two test scores is 97.

Step-by-step explanation:  Given that Kristie has taken five tests in science class. The average of all five of Kristie's test scores is 94 and the average of her last three test scores is 92.

We are to find the average score of her first two tests.

Let a1, a2, a3, a4 and a5 be teh scores of Kristle in first , second, third, fourth and fifth tests respectively.

Then, according to the given information, we have

[tex]\dfrac{a1+a2+a3+a4+a5}{5}=94\\\\\Rightarrow a1+a2+a3+a4+a5=94\times5\\\\\Rightarrow a1+a2+a3+a4+a5=470~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)[/tex]

and

[tex]\dfrac{a3+a4+a5}{3}=92\\\\\Rightarrow a3+a4+a5=92\times3\\\\\Rightarrow a3+a4+a5=276~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(ii)[/tex]

Subtracting equation (ii) from equation (i), we get

[tex](a1+a2+a3+a4+a5)-(a3+a4+a5)=470-276\\\\\Rightarrow a1+a2=194\\\\\Rightarrow \dfrac{a1+a2}{2}=\dfrac{194}{2}\\\\\Rightarrow \dfrac{a1+a2}{2}=97.[/tex]

Thus, the average of the first two test scores is 97.

Answer:

Thus, the average of the first two test scores is 97.

Step-by-step explanation:

Approximate the number below using a calculator. Round your answer to three decimal places. el.3 a) 3.534 b) 3.669 c) 3.969 d) 2.040

Answers

Answer:

a. 3.53 b. 3.61 c. 3.91 d. 2.04

Step-by-step explanation:

a. 3.534 take 4 out

b. 3.669 nine is higher then 5 so, take six makes out of one

c. 3.969 nine is higher then 5 so, take six makes out of one

d. 2.040 take zero out

above that is the answer.... hope i helped this....

The range of for y = 4/5 sin x for pi [tex]\leq[/tex] x [tex]\leq[/tex] 3pi/2 is

Choices:
4/5 [tex]\leq[/tex] y [tex]\leq[/tex] 1
-1 [tex]\leq[/tex] y[tex]\leq[/tex] 4/5
-4/5[tex]\leq[/tex] y [tex]\leq[/tex] 0
-4/5 [tex]\leq[/tex] y[tex]\leq[/tex] 4/5

Answers

Answer:

see attachment

Step-by-step explanation:

The range of [tex]\(y = \frac{4}{5}\sin x\)[/tex] for [tex]\(\pi \leq x \leq \frac{3\pi}{2}\)[/tex] is [tex]\(-\frac{4}{5} \leq y \leq 0\)[/tex] ( Option C).

To find the range of [tex]\(y = \frac{4}{5}\sin x\)[/tex] for [tex]\(\pi \leq x \leq \frac{3\pi}{2}\)[/tex], we need to determine the minimum and maximum values of sin x in the given interval and then scale them using [tex]\(\frac{4}{5}\)[/tex].

In the interval [tex]\(\pi \leq x \leq \frac{3\pi}{2}\)[/tex], the sine function is negative since it corresponds to the third and fourth quadrants on the unit circle. The minimum value of sin x in this interval is -1, and the maximum value is 0.

Now, scale these values using [tex]\(\frac{4}{5}\)[/tex]:

[tex]\(-1 \times \frac{4}{5} = -\frac{4}{5}\) (minimum)\\\\\(0 \times \frac{4}{5} = 0\) (maximum)[/tex]

Therefore, the range of [tex]\(y = \frac{4}{5}\sin x\) for \(\pi \leq x \leq \frac{3\pi}{2}\)[/tex] is [tex]\(-\frac{4}{5} \leq y \leq 0\)[/tex]. The correct choice is:

-4/5 <= y <= 0

To know more about range, refer here:

https://brainly.com/question/17440903

#SPJ2

Dagger Corporation uses direct labor-hours in its predetermined overhead rate. At the beginning of the year, the total estimated manufacturing overhead was $231,750. At the end of the year, actual direct labor-hours for the year were 17,500 hours, manufacturing overhead for the year was underapplied by $12,500, and the actual manufacturing overhead was $227,750. The predetermined overhead rate for the year must have been closest to:
1)$12.96
2)$12.30
3)$13.24
4)$11.43

Answers

Answer:

Predetermined overhead rate of the year = $12.3

Option 2 is correct.

Step-by-step explanation:

Let P = Predetermined overhead

Actual direct labor hours = 17,500

So, applied overhead = (17,500 *P)

Actual overhead = 227,750

Under applied overhead = 12,500

Applied Overhead = Actual overhead - Under applied overhead

Applied Overhead = 227,750 - 12500

Applied Overhead = 215,250

Using Formula:

215250 = (17,500 *P)

=> P = 215250/17500

P = 12.3

So, Predetermined overhead rate of the year = $12.3

Option 2 is correct.

Other Questions
Q: Which best describes the demand for consumer goods in the 1920's.Select one:a. people were less likely to buy new goods.b. the demand for consumer goods declined during the 1920's.0 C. all of these are correctd. people began buying more than they had the cash to pay for becauscould access loans and buy things on credit.NE what did southern business leader hope would be Country days scholarship rounds receive a gift of $135000. The money is invested in stock, bonds, and CDs. CDs pay 2.75% interest, bonds pay 4.5% interest, and stocks pay 10.4% interest. Country days invests $70000 more in bonds than CDs. If the annual income from the investments is $8555, how much was invested in stocks, bonds, and CDs? A growth medium is inoculated with 1,000 bacteria, which grow at a rate of 15% each day. What is the population of the culture 6 days after inoculation? Y = 1,000(1.15)6 2,313 bacteria y = 1,000(1.15)7 y = 1,000(1.5)5 y = 1,000(1.5)6 11,391 bacteria Which expression has the same value as -18-(-9)?0 -18+29 -12-(-3)-10-5 A proton is propelled at 4106 m/s perpendicular to a uniform magnetic field. 1) If it experiences a magnetic force of 4.81013 N, what is the strength of the magnetic field? (Express your answer using two significant figures.) Explain what you think Machiavelli is saying. Do you agree or disagree with him A 12-volume numbered set of books is placed randomly on a shelf. What is the probability that the books will be numbered in the correct order from left to right? Which expression is equivalent to the following complex fraction?2-1/y / 3+ 1/y Of the following elements, which could be classified as a metalloid (semimetal)? Select all that apply. (A) Mg(B) Ti(C) Ge(D) Si (E) Rn(F) Au(G) Bi(H) At (I) Br(J) B(K) Eu Indicate which property is illustrated in step 8. A. Subtraction property of equality B. Simplification C. Distributive property D. Division property of equalitystep 8: -3x/-3 = -7/3 A projectile of mass 100 kg is shot from the surface of Earth by means of a very powerful cannon. If the projectile reaches a height of 65,000 m above Earth's surface, what was the speed of the projectile when it left the cannon? (Mass of Earth 5.97x10^24 kg, Radius of Earth 6.37x10^6 m) If two lines l and m are parallel, then a reflection along the line l followed by a reflection along the line m is the same as a A. translation. B. reflection. C. rotation. D. composition of rotations. The Fratellis will be arrested if and only if the police believe Chunk. Question 9 options: 1) p q 2) p q 3) p q 4) ~p 5) p q A Styrofoam box has a surface area of 0.73 m and a wall thickness of 2.0 cm. The temperature of the inner surface is 5.0C, and the outside temperature is 25C. If it takes 8.4 h for 5.0 kg of ice to melt in the container, determine the thermal conductivity of the Styrofoam W/m-K Explain whether the fractions 3/6 and 7/14 are equivalent. Explain. **I know it's equivalent but I don't understand how. Multiply. Express your answer in simplest form. 9 1/6 1 1/11 5.How have the ancient and much older land routes contributed to exchange of ideas andgoods? Explain A science test, which is worth 100 points, consists of 24 questions. Each question is worth either 3 points or 5 points. If x is the number of 3-point questions and y is the number of 5-point questions, the system shown represents this situation. x + y = 24 3x + 5y = 100 What does the solution of this system indicate about the questions on the test? A] The test contains 4 three-point questions and 20 five-point questions. B]The test contains 10 three-point questions and 14 five-point questions. C]The test contains 14 three-point questions and 10 five-point questions. D]The test contains 20 three-point questions and 8 five-point questions. The cost of energy delivered to residences by electrical transmission varies from $0.070/kWh to $0.258/kWh throughout the United States; $0.110/kWh is the average value. (a) At this average price, calculate the cost of leaving a 40-W porch light on for two weeks while you are on vacation? (b) At this average price, calculate the cost of making a piece of dark toast in 3.00 min with a 925-W toaster?