A sun's rays are vertical at the point A on a planet. At the point B, which is 2105 miles due north of A, the angle of the sun measured to be 7.4°. See the figure. Use this information to approximate the radius and circumference of the planet.

Step-by-step explanation:

B = 1 4/5

because 1 is completely to the left, and from the distance between 1 and 2 B is at the end of the 4th of 5 sub-segments.

and 1 4/5 would be also 9/5, because B includes the 5 sub-segments (of 5) between 0 and 1. and then the 4 of 5 sub-segments between 1 and 2. so that are 9 sub-segments in total.

and each sub-segment represents 1 out of 5 (= 1/5) parts of each number interval.

therefore, we have 9×1/5 = 9/5.

1. The given equation is probably supposed to read

y'' - 2y' - 3y = 64x exp(-x)

First consider the homogeneous equation,

y'' - 2y' - 3y = 0

which has characteristic equation

r² - 2r - 3 = (r - 3) (r + 1) = 0

with roots r = 3 and r = -1. Then the characteristic solution is

[tex]y = C_1 e^{3x} + C_2 e^{-x}[/tex]

and we let y₁ = exp(3x) and y₂ = exp(-x), our fundamental solutions.

Now we use variation of parameters, which gives a particular solution of the form

[tex]y_p = u_1y_1 + u_2y_2[/tex]

where

[tex]\displaystyle u_1 = -\int \frac{64xe^{-x}y_2}{W(y_1,y_2)} \, dx[/tex]

[tex]\displaystyle u_2 = \int \frac{64xe^{-x}y_1}{W(y_1,y_2)} \, dx[/tex]

and W(y₁, y₂) is the Wronskian determinant of the two fundamental solutions. This is

[tex]W(y_1,y_2) = \begin{vmatrix}e^{3x} & e^{-x} \\ (e^{3x})' & (e^{-x})'\end{vmatrix} = \begin{vmatrix}e^{3x} & e^{-x} \\ 3e^{3x} & -e^{-x}\end{vmatrix} = -e^{2x} - 3e^{2x} = -4e^{2x}[/tex]

Then we find

[tex]\displaystyle u_1 = -\int \frac{64xe^{-x} \cdot e^{-x}}{-4e^{2x}} \, dx = 16 \int xe^{-4x} \, dx = -(4x + 1) e^{-4x}[/tex]

[tex]\displaystyle u_2 = \int \frac{64xe^{-x} \cdot e^{3x}}{-4e^{2x}} \, dx = -16 \int x \, dx = -8x^2[/tex]

so it follows that the particular solution is

[tex]y_p = -(4x+1)e^{-4x} \cdot e^{3x} - 8x^2\cdot e^{-x} = -(8x^2+4x+1)e^{-x}[/tex]

and so the general solution is

[tex]\boxed{y(x) = C_1 e^{3x} + C_2e^{-x} - (8x^2+4x+1) e^{-x}}[/tex]

2. I'll again assume there's typo in the equation, and that it should read

y''' - 6y'' + 11y' - 6y = 2x exp(-x)

Again, we consider the homogeneous equation,

y''' - 6y'' + 11y' - 6y = 0

and observe that the characteristic polynomial,

r³ - 6r² + 11r - 6

has coefficients that sum to 1 - 6 + 11 - 6 = 0, which immediately tells us that r = 1 is a root. Polynomial division and subsequent factoring yields

r³ - 6r² + 11r - 6 = (r - 1) (r² - 5r + 6) = (r - 1) (r - 2) (r - 3)

and from this we see the characteristic solution is

[tex]y_c = C_1 e^x + C_2 e^{2x} + C_3 e^{3x}[/tex]

For the particular solution, I'll use undetermined coefficients. We look for a solution of the form

[tex]y_p = (ax+b)e^{-x}[/tex]

whose first three derivatives are

[tex]{y_p}' = ae^{-x} - (ax+b)e^{-x} = (-ax+a-b)e^{-x}[/tex]

[tex]{y_p}'' = -ae^{-x} - (-ax+a-b)e^{-x} = (ax-2a+b)e^{-x}[/tex]

[tex]{y_p}''' = ae^{-x} - (ax-2a+b)e^{-x} = (-ax+3a-b)e^{-x}[/tex]

Substituting these into the equation gives

[tex](-ax+3a-b)e^{-x} - 6(ax-2a+b)e^{-x} + 11(-ax+a-b)e^{-x} - 6(ax+b)e^{-x} = 2xe^{-x}[/tex]

[tex](-ax+3a-b) - 6(ax-2a+b) + 11(-ax+a-b) - 6(ax+b) = 2x[/tex]

[tex]-24ax+26a-24b = 2x[/tex]

It follows that -24a = 2 and 26a - 24b = 0, so that a = -1/12 = -12/144 and b = -13/144, so the particular solution is

[tex]y_p = -\dfrac{12x+13}{144}e^{-x}[/tex]

and the general solution is

[tex]\boxed{y = C_1 e^x + C_2 e^{2x} + C_3 e^{3x} - \dfrac{12x+13}{144} e^{-x}}[/tex]

9514 1404 393

Answer:

  $708.87

Step-by-step explanation:

The price with tax included is ...

  660.95 + 0.0725×660.95 = 660.95(1 +0.0725) = 708.87

The total cost of the bicycle with tax is $708.87.

Answer:

$ 708.87

Step-by-step explanation:

Think that, a bicycle has listed price of $ 100,

Listed price              Tax rate            Total cost of the bicycle with sales tax

$ 100                           7.25                       107.25

$ 660.95                                                     x

Let the Total price of the bicycle be x

Now you can create a equation like this,

[tex]\frac{100}{660.95}=\frac{107.25}{x}[/tex]

Use cross multiplication, and find out the total cost of the bicycle with sales tax.

[tex]100x=660.95*107.25[/tex]

[tex]100x=70886.8875[/tex]

[tex]\frac{100x}{100} =\frac{70886.8875}{100} \\[/tex]

[tex]x=708.8688[/tex]

Therefore, the total cost of the bicycle with sales tax is,

≈ $ 708.87

Hope this helps you.

Let me know if you have any other questions :-)

9514 1404 393

Answer:

  D. choosing first second-, and third-place winners in a cooking contest​

Step-by-step explanation:

Permutations are involved when order matters. The order of people surveyed, sundae flavors, and flowers are irrelevant. The order of first-second-third is entirely relevant.

Cooking contest winners involve permutations.

Step-by-step explanation:

2008because there is no difference between the number of sold notebooks

[tex]3\dfrac 23 -1 \dfrac 45 = 3 \dfrac{10}{15} - 1 \dfrac{12}{15}[/tex]

Answer:

3(x+1)

Step-by-step explanation:

Step-by-step explanation:

Okay so, let's turn these into decimals first (rounded to nearest 2 thousandths).

2/3 = 0.66666 (repeating), to the nearest 2 thousandths would be 0.66.

-2 1/4 = -9/4 = -2.25

-1 1/2 = -3/2 = -1.5

then we set up the problem

0.66 × -2.25 × -1.5 = 2.2275 rounded 2.22 as an improper fraction 111/50 and that cannot be simplified any smaller.

Answer:

Step-by-step explanation:

Mr. Anderson's rate is:

Given options, find rates and compare with the above number:

Answer:

I don't see any statements, but Tamara paid less. She paid 19.8 after the discount. David spent a little more at 19.95

Answer:

7/2(1/2)^(n-1)

Step-by-step explanation:

multiplied by 1/2 each time, and first one is 7/2, so 7/2(1/2)^(n-1)

Answer:

Fertilizer puts nitrogen into the soil, so using fertilizer puts more nitrogen into the carbon cycle.

When you use fertilizer, its because a certain plant you are planting uses all the nitrogen in the soil, so it won't grow next time. Too much fertilizer, though, would burn up your plant (not literally). Some plants put their own nitrogen into the soil. I can't think of one off the top of my head, but I believe potatoes do. Anyways, this is where crop rotation came into play.

Things like corn take a lot of nitrogen, so the next time you had to plant whatever plant potatoes, which again may be wrong, in order to get nitrogen for the corn to grow next season. Today we have fertilizer, so we can give them nitrogen while they grow, instead of putting in other plants, taking more time.

So really, it doesn't do much, because your plant takes all the nitrogen that the Fertilizer adds.

Answer:

People have been converting atmospheric nitrogen into nitrogen fertilizers and then applying the fertilizers to plants in to grow more crops. This has previously been quite effective, allowing individuals to farm on previously unproductive lands, and provide adequate food for expanding populations of people. Unfortunately, fertilizers are frequently overused, which can lead to issues.

Nitrogen from fertilizers excretes into soils, typically promoting the growth of weeds rather than native vegetation. Nitrogen then washes into streams, resulting in a nutrient overload, a phenomenon known as eutrophication.

Eutrophication causes aquatic weeds to proliferate excessively in freshwater lakes. These aquatic weeds  occasionally occupy entire lakes, streams, or rivers. Green algae cloud the water, and gooey algal slime covers the shallow rocks. 

When nitrogen-rich waters flow down into the ocean, they worsen the situation. High nitrogen concentrations in the Mississippi River Delta have generated a 'dead zone' where the water flows into the Gulf of Mexico. This has occurred every summer for over 30 years. In 2001, this dead zone, where oxygen levels are too low for species to thrive, encompassed over 8000 square miles of water. It occurs when nitrogen in the water enables algae to quickly grow out of control.

Step-by-step explanation:

Great article to look at for more information -

https://www.nytimes.com/2017/07/27/climate/nitrogen-fertilizers-climate-change-pollution-waterways-global-warming.html

x = the whole pie.

well, Don ate (1/8)x, how much was it left?  [tex]x -\cfrac{1}{8}x\implies \cfrac{x}{1} -\cfrac{x}{8}\implies \cfrac{8x-x}{8}\implies \cfrac{7x}{8}[/tex]

well, so that's the remainder.

Then Ron ate 1/7 of the remainder [tex]\cfrac{7x}{8}\div 7\implies \cfrac{7x}{8}\div \cfrac{7}{1}\implies \cfrac{7x}{8}\cdot \cfrac{1}{7}\implies \cfrac{x}{8}[/tex]

well, how much is it left?  [tex]\stackrel{\textit{Don leftover}}{\cfrac{7x}{8}}-\stackrel{\textit{Ron's bite}}{\cfrac{x}{8}}\implies \cfrac{6x}{8}\implies \cfrac{3x}{4}[/tex]

well, there are 5 friends how much did each one get from the whole pie?

[tex]\cfrac{3x}{4}\div 5\implies \cfrac{3x}{4}\div \cfrac{5}{1}\implies \cfrac{3x}{4}\cdot \cfrac{1}{5}\implies \implies \cfrac{3x}{20}\implies \stackrel{\textit{each friend}}{\boxed{\cfrac{3}{20}x}}[/tex]

The number of hours Jeremy spent in the air is 16 hours.

He flew 8 times last week for work.

Each flight was two hours long.

Therefore, each flight, he spends two hours in the air.

Now he took this two hours flight for 8 times.

Therefore, the number of hours he spend in the air can be calculated as follows:

number of hours spent in the air = 8 × 2

number of hours spent in the air = 16 hours

Therefore, he spent 16 hours in the air.

learn more on hours here: https://brainly.com/question/14093155

#SPJ1

Answer:

answer for question 7. 0.17×70 = $11.9

Answer:

Question 1:

bill = $70

tip percentage = 17%

so tip = 70x(17/100)

= 11.9$

Question 2:

total voters = 20500

supported voters percentage = 49%

so supported voters = 20500x(49/100)

= 10045

Question 3:

price = 154$

vat percentage =5%

so vat = 154x(5/100)

= 7.7$

Answer: 0

Step-by-step explanation:  6-(2)(3)                                                                       6-6                                                                                                                             0

Suppose {xn} is increasing and has a subsequence {xnk} which converges to L. We will prove that {xn} itself converges to L.

For any ϵ>0, we want to find an integer Nϵ such that |xn−L|≤ϵ for any n≥Nϵ.

Since {xnk} is increasing and converges to L, we can find kϵ such that for any k≥kϵ, −ϵ<xnk−L<0.

Take Nϵ=nkϵ, then for any n≥Nϵ, xnkϵ≤xn≤L, so −ϵ≤xnkϵ−L≤xn−L≤0.

Similarly, we can prove when {xn} is decreasing

Answer:True

Step-by-step explanation:

There is a constant rate of change. For x, it'd be +1. For y, it'd be +3.

Vote brainliest please!

Answer:

true

Step-by-step explanation:

This is because the slope is y= 3x, you can prove that by plugging in the x values, and if they equal the y then that slope is right.

Answer:

(3*5)+(19*3)

Step-by-step explanation:

both numbers GCF is 3.

(3*5)=15

(19*3)=57

15+57=72

Hope that helps

[tex] \rightarrow [/tex] 12.5%

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

To solve, use the formula:

[tex] \rightarrow \: \rm Percent \: of \: Increase = \frac{Amount \: of \: Increase}{Original \: Amount} \\ [/tex]

Solve.

[tex] \rightarrow \: \rm = \frac{16 - 12}{12} [/tex] Amount of increase: 16 - 12 = 2

[tex] \rightarrow \: \rm = \frac{2}{16} [/tex] Simplify.

[tex] \rightarrow \: \rm = \frac{x}{100} = \frac{1}{8}[/tex] Write the fraction as a percent.

[tex] \rightarrow [/tex]8x = 100 Find the product of the extreme and the means.

[tex] \rightarrow \: \rm = \frac{8x}{8} = \frac{100}{8}[/tex] Divide both sides by 8.

[tex] \rightarrow [/tex]x = 12.5

Therefore, the percentage of increase in the item is 12.5%.

Answer:

12

Step-by-step explanation:

Problem 14, Part (a)

The given equation y = 2(x-10)+3 has a slope of m = 2. Anything parallel to this will also have the same slope, but a different y intercept.

Let's find the point slope form of the parallel line through (-4,1)

[tex]y-y_1 = m(x - x_1)\\\\y-1 = 2(x - (-4))\\\\y-1 = 2(x + 4)\\\\[/tex]

Now solve for y to get the slope intercept form.

[tex]y-1 = 2(x + 4)\\\\y = 2(x + 4)+1\\\\y = 2x + 8+1\\\\y = 2x + 9\\\\[/tex]

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

Problem 14, Part (b)

The original slope is m = 2. Apply the negative reciprocal to go from 2/1 to -1/2. The perpendicular slope is -1/2.

Using the same point (-4,1), we find that the point slope form is...

[tex]y-y_1 = m(x - x_1)\\\\y-1 = -\frac{1}{2}(x - (-4))\\\\y-1 = -\frac{1}{2}(x+4)\\\\[/tex]

Now solve for y

[tex]y-1 = -\frac{1}{2}(x+4)\\\\y = -\frac{1}{2}(x+4)+1\\\\y = -\frac{1}{2}x-2+1\\\\y = -\frac{1}{2}x-1\\\\[/tex]

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

Problem 15, Part (a)

Anything parallel to Ax+By = C will be in the form Ax+By = D. The only thing changes is the C becomes D, where [tex]C \ne D[/tex]. If C = D, then we'd be talking about the exact same line rather than two parallel lines.

We're given 5x+2y = 7. The answer is in the form 5x+2y = D. Plug in (x,y) = (0,10) to find the value of D

5x+2y = D

D = 5x+2y

D = 5(0)+2(10)

D = 20

The equation 5x+2y = D updates to 5x+2y = 20

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

Problem 15, Part (b)

If you are given Ax+By = C, then anything perpendicular to this is Bx-Ay = D. Here it's possible that C = D; however, it's likely that they'll be different.

The given equation 5x+2y = 7 is perpendicular to anything of the form 2x-5y = D. We'll plug in the given point to find D.

2x-5y = D

D = 2x-5y

D = 2(0)-5(10)

D = -50

Answer:

1

Step-by-step explanation:

because... it is

[tex]\text{Area of rectangle} = \text{Length} \times \text{Width}\\\\\\\implies \text{Width} = \dfrac{\text{Area of reactangle}}{\text{Length}} = \dfrac{x^2 +8x +12}{x+6} = \dfrac{x^2 + 6x +2x +12}{x+6}\\\\\\\\ = \dfrac{x(x+6) +2(x+6)}{x+6}=\dfrac{(x+6)(x+2)}{x+6} = x+2[/tex]

Answer:

Maybe 9 oz, if I’m wrong sorry! D: