Test for exactness. If exact, solve it directly. Otherwise, use integrating factors to solve it. Solve the IVP (if given). 2xy + (x^2) y' = 0
sin(x) cos(y) + cos(x) sin(y) y' = 0
(x^2) + (y^2) - 2xyy' = 0
e^(2x).(2 cos(y) - sin(y) y') = 0, where y(0) = 0​

Answers

Answer 1

• 2xy + x ² y' = 0

This DE is exact, since

∂(2xy)/∂y = 2x

∂(x ²)/∂x = 2x

are the same. Then there is a solution of the form f(x, y) = C such that

f/∂x = 2xy   ==>   f(x, y) = x ² y + g(y)

f/∂y = x ² = x ² + dg/dy   ==>   dg/dy = 0   ==>   g(y) = C

==>   f(x, y) = x ² y = C

• sin(x) cos(y) + cos(x) sin(y) y' = 0

is also exact because

∂(sin(x) cos(y))/∂y = -sin(x) sin(y)

∂(cos(x) sin(y))/∂x = -sin(x) sin(y)

Then

f/∂x = sin(x) cos(y)   ==>   f(x, y) = -cos(x) cos(y) + g(y)

f/∂y = cos(x) sin(y) = cos(x) sin(y) + dg/dy   ==>   dg/dy = 0   ==>   g(y) = C

==>   f(x, y) = -cos(x) cos(y) = C

• x ² + y ² - 2xyy' = 0

is not exact:

∂(x ² + y ²)/∂x = 2x

∂(-2xy)/∂y = -2x

So we look for an integrating factor µ(x, y) such that

µ (x ² + y ²) - 2µxyy' = 0

becomes exact, which would require that these be equal:

∂(µ (x ² + y ²))/∂y = (x ² + y ²) ∂µ/∂y + 2µy

∂(-2µxy)/∂x = -2xyµ/∂x - 2µy

Observe that if µ(x, y) = µ(x), then ∂µ/∂y = 0 and ∂µ/∂x = dµ/dx, so we would have

2µy = -2xy dµ/dx - 2µy

==>   -2xy dµ/dx = 4µy

==>   dµ/µ = -2/x dx

Integrating both sides gives

∫ dµ/µ = ∫ -2/x dx   ==>   ln|µ| = -2 ln|x|   ==>   µ = 1/x ²

So in the modified DE, we have

(1 + y ²/x ²) - 2y/x y' = 0

which is now exact and ready to solve, since

∂(1 + y ²/x ²)/∂y = 2y/x ²

∂(-2y/x)/∂x = 2y/x ²

We get

f/∂x = 1 + y ²/x ²   ==>   f(x, y) = x - y ²/x + g(y)

f/∂y = -2y/x = -2y/x + dg/dy   ==>   dg/dy = 0   ==>   g(y) = C

==>   f(x, y) = x - y ²/x = C

• exp(2x) (2 cos(y) - sin(y) y' ) = 0

is exact, since

∂(2 exp(2x) cos(y))/∂y = -2 exp(2x) sin(y)

∂(-exp(2x) sin(y))/∂x = -2 exp(2x) sin(y)

Then

f/∂x = 2 exp(2x) cos(y)   ==>   f(x, y) = exp(2x) cos(y) + g(y)

f/∂y = -exp(2x) sin(y) = -exp(2x) sin(y) + dg/dy   ==>   dg/dy = 0   ==>   g(y) = C

==>   f(x, y) = exp(2x) cos(y) = C

Given that y = 0 when x = 0, we find that

C = exp(0) cos(0) = 1

so that the particular solution is

exp(2x) cos(y) = 1


Related Questions


A train is traveling at a speed of 60 miles per hour. What happens to the number of miles when the number of hours
changes?
Abebe babe

Answers

Answer:

It multiplies

Step-by-step explanation:

if the number of hours changes to example to 2 then you multiply 60 by 2 resulting in 120miles in 2 hours

Britany wants to read a book. In her room, she has 5 mysteries, 15 historical fictions, 12 modern fantasies, and 7 blographies.
How many different choices are available?


pleaseee

Answers

Answer:

39

Step-by-step explanation:

5 + 15 + 12 + 7 = 39

Answer:

39

Step-by-step explanation:

5 + 15 = 20, 12 + 7 = 19, 20 + 19 = 39.

What is the value of the expression i 0 × i 1 × i 2 × i 3 × i 4?
1
–1
i
–i

Answers

Answer:

Answer is -1

Step-by-step explanation:

i1 = i 

i2 = -1 

i3 = -i

i4 = 1

i0 × i1 × i2 × i3 × i4 = 1 × i  × (- 1) × (- i) × 1 = i2 = - 1

Answer:the answer is -1

Step-by-step explanation:

Using the Time Series Data for the US Nuclear Electric Power Production, calculate the exponential smoothing forecasts for 2005 through 2010 using alpha equals 0.2. Find the forecast error for each time period. If there is n

Answers

Answer:

????????????

I don't know

Find the medien: 16,12,10,15,7,9,16

Answers

Answer:

12

Step-by-step explanation:

arrange the numbers in ascending order and cross out from either side till you have a middle line

FINAL ANSWER:

12

Step-by-step explanation:

Median is the middle number in the data set.

so first of ... we need to arrange the group of numbers from lower to greater.

16, 12, 10, 15, 7, 9, 16 ⇒ 7, 9, 10, 12, 15, 16, 16

Now that we have arranged the numbers from least to greatest all we need to do is to find the middle number of the data set (data set? they are the group of numbers)

Ok, so what you want to do here is to just count the numbers until you get to the middle number of the data set...

7, 9, 10, 12, 15, 16, 16

the median in the given data set is 12.

I hope this helps you!!! Let me know if my answer is incorrect or not...

HAVE A GREAT DAY AND GOD BLESS YOU ;)!!!

There are three separate, equal-size boxes, and inside each box there are four separate small boxes, and inside each of the small boxes there are three even smaller boxes. how many boxes are there all together?

Answers

Answer:

There are 51 boxes all together.

Step-by-step explanation:

Since there are three separate, equal-size boxes, and inside each box there are four separate small boxes, and inside each of the small boxes there are three even smaller boxes, to determine how many boxes are there all together, the following calculation must be done:

3 + 3 x 4 + 3 x 4 x 3 = X

3 + 12 + 36 = X

51 = X

Therefore, there are 51 boxes all together.

The wholesale price of 6 oz plastic bottles is 6 cents how many plastic bottles can be purchased for $98.41

Answers

Answer:

1640

Step-by-step explanation:

Take the total amount and divide by the amount for one

Make sure to write 6 cent in dollar form (.06)

98.41 / .06

1640.1666

Round down since we need to buy whole bottles

1640

Find the slope of the line #67

Answers

Vas happenin
Hope your day is going well
The slope form is y2-y1/x2-x1
So I’m going to use (1,1) (-1,4)
Y2= 4
Y1=1
X2= -1
X1= 1
Then you plug in those equations 4-1/ -1 -1
3/-2 that’s the fraction form
The decimal form is -1.5 this is the slope
Hope this helps *smiles*

Simplify 7a – 11b + 4ab – 6a + 5b.

Answers

7a-6a-11b+5b+4ab
=a-6b+4ab
Final answer

Perimeter (numerical)

Answers

Answer:

270 m

Step-by-step explanation:

Add up all the sides

P = 19 +18.8+18.8 +18.8+18.8+40.8+19+40.8+18.8+18.8+18.8+18.8

P = 270 m

Michael drove 210 miles in 3 1/2. Jordan drove 330 miles in 6 hours. Which is an accurate comparison of the rates at which the two people drove?

Answers

Michael = 210 / 3.5 = 60 miles per hour

Jordan = 330/ 6 =55 miles per hour

Jordan drove 5 miles per hour slower than michael

Do number 7 plz finding QR​

Answers

Answer:

QR = sqrt(147)

Step-by-step explanation:

Since this is a right triangle, we can use the Pythagorean theorem

a^2 + b^2 = c^2

7^2 + QR^2 = 14^2

49 + QR^2 = 196

QR^2 = 196-49

QR^2 = 147

Taking the square root of each side

QR = sqrt(147)

find the constant of variation k for the direct variation. 4x = -y

Answers

Answer:

k = - 4

Step-by-step explanation:

The equation representing direct variation is

y = kx ← k is the constant of variation

Given

4x = - y ( multiply both sides by - 1 )

- 4x = y , that is

y = - 4x ← in standard form

with k = - 4

A trough has ends shaped like isosceles triangles, with width 2 m and height 5 m, and the trough is 18 m long. Water is being pumped into the trough at a rate of 8 m3/min. At what rate (in m/min) does the height of the water change when the water is 2 m deep

Answers

9514 1404 393

Answer:

   5/9 m/min

Step-by-step explanation:

The depth of the water is 2/5 of the depth of the trough, so the width of the surface will be 2/5 of the width of the trough:

  2/5 × 2 m = 4/5 m

Then the surface area of the water is ...

  A = LW = (18 m)(4/5 m) = 14.4 m²

The rate of change of height multiplied by the area gives the rate of change of volume:

  8 m³/min = (14.4 m²)(h')

  h' = (8 m³/min)/(14.4 m²) = 5/9 m/min

20 slips of paper are put into a bag numbered from 1 to 20. One slip is randomly selected from the bag. We are interested in selecting even numbers. What is the probability of selecting an even number from the bag?

Answers

Answer:

2/5

Step-by-step explanation:

Answer:

Step-by-step explanation:

There are 10 even numbers from 1 to 20

2 4 6 8 10 12 14 16 18 20

There 20 possible choices.

P(Even) = 10 /20 = 1/2

Nadia needs 3/4 cup of orange juice for a punch recipe. She will double the recipe to make
punch for a party. Which statement is true?

Answers

Answer:

she will be using more orange juice

Answer:

she will be using more orange juice

A formula for the normal systolic blood pressure for a man age A, measured in mmHg, is given as P = 0.006A*2-0.02A + 120. Find the age of a man whose normal blood pressure measures 129 mmHg. Round your answer to the nearest year. The man would be ? years old.​

Answers

Answer:

The man would be 40 years old.

Step-by-step explanation:

Blood pressure as function of age:

Is given by the following equation:

[tex]P = 0.006A^2 - 0.02A + 120[/tex]

Find the age of a man whose normal blood pressure measures 129 mmHg.

This is A for which P = 129. So

[tex]129 = 0.006A^2 - 0.02A + 120[/tex]

[tex]0.006A^2 - 0.02A - 9 = 0[/tex]

Solving a quadratic equation:

Given a second order polynomial expressed by the following equation:

[tex]ax^{2} + bx + c, a\neq0[/tex].

This polynomial has roots [tex]x_{1}, x_{2}[/tex] such that [tex]ax^{2} + bx + c = a(x - x_{1})*(x - x_{2})[/tex], given by the following formulas:

[tex]x_{1} = \frac{-b + \sqrt{\Delta}}{2*a}[/tex]

[tex]x_{2} = \frac{-b - \sqrt{\Delta}}{2*a}[/tex]

[tex]\Delta = b^{2} - 4ac[/tex]

In this question:

Quadratic equation with [tex]a = 0.006, b = -0.02, C = -9[/tex]. So

[tex]\Delta = (-0.02)^2 - 4(0.006)(-9) = 0.2164[/tex]

[tex]A_{1} = \frac{-(-0.02) + \sqrt{0.2164}}{2*(0.006)} = 40.4[/tex]

[tex]A_{2} = \frac{-(-0.02) - \sqrt{0.2164}}{2*(0.006)} = -37.1[/tex]

Age has to be a positive number, so rounding to the nearest year:

The man would be 40 years old.

The triangles below are similar (being similar means there is a proportional relationship between the measures of each of the sides). What is the length of ED? (HINT: You can solve this question by using the MATH Ratio Table)

Answers

Answer:  B)  18 cm

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

Work Shown:

ED/DF = AB/AC

x/24 = 12/16

16x = 24*12

16x = 288

x = 288/16

x = 18

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

Explanation:

Because the triangles are similar, we can form the proportion shown above. There are many variations of the proportion that can happen, but they all lead to the same result x = 18.

So for instance, another proportion you could solve is ED/AB = DF/AC.

The key is to keep up the same pattern when forming the ratios.

What I mean by that is when I formed ED/DF I divided the vertical side over the horizontal side for triangle EDF. So to form the second fraction, we must do the same division (vertical over horizontal) for triangle ABC.

The value of 33 + 42 = ___.

Numerical Answers Expected!

Answer for Blank 1:

Answers

Answer:

3^3 + 4^2 = 43

Step-by-step explanation:

Please write the numbers like this 3^3 + 4^2 next time

3^3 + 4^2 =

Solve for 3^3

3^3 = 3 • 3 • 3 = 27

Solve for 4^2

4^2 = 4 • 4 = 16

Add 27 and 16

27 + 16 = 43

[tex] \sf Q) \: {3}^{3} + {4}^{2} = {?}[/tex]

[tex] \sf \to \: {3}^{3} + {4}^{2} [/tex]

[tex] \sf \to \: 27 + 16= 43 [/tex]

Thus, the value is 43.

I need help with this ​

Answers

Answer:

D.

Step-by-step explanation:

According to converse of the Pythagorean Theorem, that if the square of the third side (longest side) of a triangle equals the sum of the other two shorter sides, therefore, the triangle formed must be a right triangle.

From the side lengths given, the following satisfies the Pythagorean triple:

5² + 12² = 13².

Therefore, the procedure to use to confirm the converse of the Pythagorean Theorem would be to draw the two shortest side, 5 cm and 12 cm, so that a right angle will be between them. The side measuring 13 cm should therefore fit in to form a right triangle.

construct an angle that bisect 120°​

Answers

Answer:

just make a 120 angle and divide it by 2, 60.

A certain brand of coffee comes in two sizes. An 11.5-ounce package costs $.4.24 . A 27.8-ounce package costs $9.98.
Find the unit price for each size. Then state which size is the better buy based on the unit price.

Round your answers to the nearest cent.

Answers

Answer:

Small (11.5) is 37 cents per ounce.

Large (27.8) is 36 cents per ounce.

27.8 ounces is the better buy.

Simplify: 3.5 x 10^-2 + 2.3 x 10^-2

Answers

Given:

The given expression is:

[tex]3.5\times 10^{-2}+2.3\times 10^{-2}[/tex]

To find:

The simplified form of the given expression.

Solution:

We have,

[tex]3.5\times 10^{-2}+2.3\times 10^{-2}[/tex]

It can be written as:

[tex]=(3.5+2.3)\times 10^{-2}[/tex]

[tex]=5.8\times 10^{-2}[/tex]

Therefore, the simplified form of the given expression is [tex]5.8\times 10^{-2}[/tex].

Which graph represents y = |xl?
A
B
C
D

Answers

Answer:

B

Step-by-step explanation:

The equation represented in the question is the parent absolute value question. If you know the different parent functions, then the answer is obvious because absolute value equations always form a V. However, if you do not do this then you can create a table and plugin values. Plugin numbers like 0, -1, and 1 for X and solve for Y. Finally, graph these points and see what graph best fits. If needed you can also plug in more points.

Answer:

B.

Step-by-step explanation:

I got it correct on the warm up

If there is a die that has 12 sides, that are numbered 1 to 12, what is the probability that she will roll either a 3 or a 9

Answers

Answer:

2/12 = 1/6

Step-by-step explanation:

To find the probability of something with an equal chance of each outcome, we can apply the formula (number of favorable outcomes)/(number of total outcomes). Because there is an equal chance for each side of the die to be landed on, we can apply this.

On a 12 sided die, there are 12 sides. Two of those sides are 3 and 9. Therefore, there are two favorable outcomes (3 and 9). There are 12 sides to choose from, so there are 12 total outcomes, making the probability 2/12 = 1/6

Norman and Suzanne own 35 shares of a fast food restaurant stock and 63 shares of a toy company stock. At the close of the markets on a particular day in​ 2004, their stock portfolio consisting of these two stocks was worth ​$1596.00. The closing price of the fast food restaurant stock was ​$19 more per share than the closing price of the toy company stock on that day. What was the closing price of each stock on that​ day? The price per share of the fast food restaurant stock is ​

Answers

Answer:

closing price of the fast food stock was $997.50

closing price of the toy company stock was $598.50

the price per fast food share was $28.50

Step-by-step explanation:

x = price per share fast food

y = price per share toy company

35x + 63y = 1596

x = y + 19

=>

35(y+19) + 63y = 1596

35y + 665 + 63y = 1596

98y + 665 = 1596

98y = 931

y = $9.50

=>

x = 9.5 + 19 = $28.50

the value of the whole fast food stock was

35x = 35×28.5 = $997.50

the cake if the whole toy company stock was

63y = 63×9.5 = $598.50

The theoretical mean of a distribution is also known as its ______________.

Answers

Answer:

skewness

Step-by-step explanation:

Average.

The average of a set of observations is the most important and useful measure of statistics and is a position measure, as it shows the positions of the numbers to which it refers. The average value is involved in several types of statistics and is examined in almost all statistical distributions. It is generally defined as the sum of the observations by their number. That is, it is the mathematical operation of finding the "mean distance" between two or more numbers.

Learn more about averages in https://brainly.com/question/22390452

If 1 kilogram (kg) is equal to about 2.2046 pounds (lbs.), what is the value of 1kg/2.2046lbs? What is the value of 2.2046lbs/1kg?

Answers

Step-by-step explanation:

The relation between kg and lbs is :

1 kg = 2.2046 lbs

We need to find the values of 1kg/2.2046lbs and 2.2046lbs/1kg.

So,

[tex]\dfrac{1\ kg}{2.2046\ lbs}=\dfrac{2.2046\ lbs}{2.2046\ lbs}\\\\=1[/tex]

and

[tex]\dfrac{2.2046\ lbs}{1\ kg}=\dfrac{2.2046\ lbs}{2.2046\ lbs}\\\\=1[/tex]

Hence, this is the required solution.

Answer:

Both are same as 1.

Step-by-step explanation:

1 kg = 2.2046 lbs

So,

[tex]\frac{1 kg}{2.2046 lbs }=\frac{1 kg }{1 kg} = 1[/tex]

And

[tex]\frac{2.2046 lbs}{1 kg }=\frac{1 kg }{1 kg} = 1[/tex]

Solve this equation for x. Round your answer to the nearest hundredth. 0.77 = log x​

Answers

Answer:

x ≈ 5.89

General Formulas and Concepts:

Pre-Algebra

Equality Properties

Algebra II

Exponential to Logarithmic:                                                                             [tex]\displaystyle b^m=x \rightarrow log_bx=m[/tex]

Step-by-step explanation:

Step 1: Define

Identify

0.77 = log(x)

Step 2: Solve for x

[Equality Property] Raise both sides to the 10th power:                                [tex]\displaysytle 10^{0.77} = 10^{logx}[/tex]Simplify:                                                                                                             [tex]\displaysytle x = 10^{0.77}[/tex]Evaluate:                                                                                                           [tex]\displaysytle x = 5.88844[/tex]

The director of special events for Sun City believed that the amount of money spent on fireworks displays on the 4th of July was predictive of attendance at the Fall Festival held in October. She gathered the following data to test her suspicion.

4th of July ($000) Fall Festival (000)
10.6  8.8
 8.5  6.4
12.5 10.8
 9.0 10.2
 5.5   6.0
12 11.1
 8.0   7.5
 7.5   8.4
 9.0   9.5
10   9.8
 7.5   6.6
10 10.1
 6.0   6.1
12 11.3
10.5   8.8

Required:
Determine the regression equation. Is the amount spent on fireworks related to attendance at the Fall Festival? Conduct a hypothesis test to determine if there is a problem with autocorrelation.

Answers

Answer:

The complete question and its solution in the attached file please find it.

Step-by-step explanation:

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