All categories

3 years ago

Solve the equation (1 + x²)dy +xydx= 0

Mathematics

1 answer:

Tatiana [17]3 years ago

7 0

Answer:

$y=\frac{c}{\sqrt[]{x^2+1} }$

Step-by-step explanation:

(1 + x²)dy +xydx= 0

$(1+x^2)dy=-xydx\\\frac{1}{y}dy=\frac{-x}{x^2+1}dx\\$

Integrate both side

$lny=-\frac{1}{2} ln(x^2+1)+c\\y=\frac{c}{\sqrt[]{x^2+1} }$

You might be interested in

g A psychic was tested for extrasensory perception (ESP). The psychic was presented with cards face down and asked to determine

diamong [38]

Answer:

Step-by-step explanation:

Hello!

The objective is to test ESP, for this, a psychic was presented with cards face down and asked to determine if each of the cards was one of four symbols: a star, cross, circle, square.

Be X: number of times the psychic identifies the symbols on the cards correctly is a size n sample.

p the probability that the psychic identified the symbol on the cards correctly

You have to calculate the sample size n to estimate the proportion with a confidence level of 95% and a margin of error of d=0.01

The CI for the population proportion is constructed "sample proportion" ± "margin of error" Symbolically:

p' ± $Z_{1-\alpha /2} * (\sqrt{\frac{p'(1-p')}{n} } )$

Where $d= Z_{1-\alpha /2} * (\sqrt{\frac{p'(1-p')}{n} } )$ is the margin of error. As you can see, the formula contains the sample proportion (it is normally symbolized p-hat, in this explanation I'll continue to symbolize it p'), you have to do the following consideration:

Every time the psychic has to identify a card he can make two choices:

"Success" he identifies the card correctly

"Failure" he does not identify the card correctly

If we assume that each symbol has the same probability of being chosen at random P(star)=P(cross)=P(circle)=P(square)= 1/4= 0.25

Let's say, for example, that the card has the star symbol.

The probability of identifying it correctly will be P(success)= P(star)= 1/4= 0.25

And the probability of not identifying it correctly will be P(failure)= P(cross) + P(circle) + P(square)= 1/4 + 1/4 + 1/4= 3/4= 0.75

So for this experiment, we'll assume the "worst case scenario" and use p'= 1/4 as the estimated probability of the psychic identifying the symbol on the card correctly.

The value of Z will be $Z_{1-\alpha /2}= Z_{0.975}= 1.96$

Now using the formula you have to clear the sample size:

$d= Z_{1-\alpha /2} * (\sqrt{\frac{p'(1-p')}{n} } )$

$\frac{d}{Z_{1-\alpha /2}} = \sqrt{\frac{p'(1-p')}{n} }$

$(\frac{d}{Z_{1-\alpha /2}})^2 =\frac{p'(1-p')}{n}$

$n*(\frac{d}{Z_{1-\alpha /2}})^2 = p'(1-p')$

$n = p'(1-p')*(\frac{Z_{1-\alpha /2}}{d})^2$

$n = (0.25*0.75)*(\frac{1.96}{0.01})^2= 7203$

To estimate p with a margin of error of 0.01 and a 95% confidence level you have to take a sample of 7203 cards.

I hope this helps!

5 0

3 years ago

Read 2 more answers

Write the ratio of the area of a circle with radius r to the circumference of the same circle

Goshia [24]

Answer:

$\frac{r}{2\pi r} =\frac{1}{2\pi }$

Step-by-step explanation:

A ratio is a comparison of two quantities and can be written in several forms including fractions. It is most commonly written in fraction form or a:b.

To write a ratio, we count the number of each quantity we are comparing or use the variable for that quantity. We write radius:circumference. Recall, the circumference of a circle can be found using $\pi d$ or $2\pi r$ .

We write r: $\pi d$ or r: $2\pi r$ .

We can also write in fraction form:

$\frac{r}{\pi d}$ or $\frac{r}{2\pi r} =\frac{1}{2\pi }$

6 0

3 years ago

56 points for whoever answers correctly !

vladimir2022 [97]

We need to use what we know about rectangles to get:

Total length = 2*W + 8ft
Total width = W + 8ft

2) area = 2*W^2 + 24ft*W + 64ft^2

<h3>Working with rectangles:</h3>

We know that rectangles are defined by two measures, width W and length L.

Here we do know that the length of the pool is twice the width, and the width is W, then the length of the pool is:

L = 2*W

And we also have a sidewalk of 4ft all around the pool, now we want to get:

1) The total length and the total width.

This will be equal to the length/width of the pool <u>plus twice the width of the sidewalk</u> (we add it twice because is in both ends) then we have:

Total length = L + 2*4ft = 2*W + 8ft
Total width = W + 2*4ft = W + 8ft

2) Now we want to get an expression for the total area of the pool.

Remember that for a rectangle the area is just the product between the width and the length, so to get the area of the pool with the sidewalk we just take:

area = (total length)*(total width)

area = (2*W + 8ft)*(W + 8ft) = 2*W^2 + 3*W*8ft + 64ft^2

area = 2*W^2 + 24ft*W + 64ft^2

This is the equation that gives the total area as a function of W, the width of the pool.

If you want to learn more about rectangles, you can read:

brainly.com/question/17297081

6 0

3 years ago

Solve each equation. Show your work<br><br> 13a=-5<br> 12−b=12.5<br> -0.1=-10c

amid [387]

1) 13a=-5
Make a the subject of the formula by dividing both sides by 13(the coefficient of a)
13a/13=-5/13
Therefore a= -0.385

The second one). 12-b= 12.5
You take the 12 to the other side making b subject of the formula (-b in this case)
-b= 12.5-12
-b= 0.5
(You cannot leave b with a negative sign so you will divide both sides by -1 to cancel out the negative sign)

-b/-1= 0.5/-1
Therefore b=-0.5

The third one). -0.1= -10c
You will divide both sides by the coefficient of c(number next to c) which is -10
-0.1/-10= -10c/-10

Hence, c= 0.01

5 0

3 years ago

What is the solution to the linear equation?

gizmo_the_mogwai [7]

Answer:

p = 30/1/3 or 91/3 or 30.33

Step-by-step explanation:

2 + p = 7/3 + 30

p = 32/1/3 - 2

p = 30/1/3

3 0

3 years ago

Solve the equation (1 + x²)dy +xydx= 0​

Solve the equation (1 + x²)dy +xydx= 0