Giải phương trình vi phân cấp 2

Answer:

each movie costs $2.75, each video game costs $6.75

Step-by-step explanation:

x = movies, y = video games

7x + 9y = 80

5x + 3y = 34

simplified to

x = 11/4 , y = 27/4

Answer:

WHAT

Step-by-step explanation:

Answer:

S = 38.4 centimeters.

Step-by-step explanation:

Given the following data;

To find the length of the arc of a circle;

A full circle measures an angle of 360 degrees.

π = 180°

So; Angle, A = 360° = 2π

Therefore, a full circle is equal to 2π in terms of radians (rads).

Also, the circumference (the length of an arc) of a circle is equal to 2πr or Ar.

Mathematically, the length of the arc of a circle is given by the formula;

S = rA

Where;

Substituting into the formula, we have;

S = 12 * 3.2

S = 38.4 centimeters.

Answer:

300 million(1+ 36 million) y

Step-by-step explanation:

Answer:

x = -40

General Formulas and Concepts:

Pre-Algebra

Equality Properties

Step-by-step explanation:

Step 1: Define

Identify

50 - 5x = 250

Step 2: Solve for x

Answer:

down by 1 unit and left by 4 units

Step-by-step explanation:

Given f(x) then f(x) + c is a vertical translation of f(x)

• If c > 0 then a shift up of c units

• If c < 0 then a shift down of c units

Given f(x) then f(x + a) is a horizontal translation of f(x)

• If a > 0 then a shift left of a units

• If a < 0 then a shift right of a units

Then

g(x) = (x + 4)² - 1

is f(x) shifted down by 1 unit and shifted left by 4 units

9514 1404 393

Answer:

Step-by-step explanation:

The side length of a square is 1/4 of the perimeter, so the side length of the square orchard is (1600 m)/4 = 400 m.

The area of a square is the square of the side length, so the area of the orchard is (400 m)² = 160,000 m².

A hectare is 10,000 m², so the area of the orchard in hectares is ...

  16·(10,000 m²) = 16 ha

Answer:

8

Step-by-step explanation:

11 + x = 19

Subtract 11 from each side

11+x -11 = 19-11

x = 8

Answer:

8

Step-by-step explanation:

11 + box = 19

=> box = 19 - 11

.°. box = 8

Answer:

for which question???????????????

Answer:

Ok please tell me your question because you forgotten the question your asking dor

9514 1404 393

Answer:

Step-by-step explanation:

A graphing calculator can quickly show you the boundaries of the feasible region, and can calculate the values of the objective function.

Answer:

A. True

Step-by-step explanation:

Answer:

VERTEX: (0.75,25)    

Step-by-step explanation:

the vertex will be at [-b/2a, f(-b/2a)]

−16x2 + 24x + 16

4(-4x^2 + 6x +4)

a = -4, b=6,c=4

-6/-8 = 3/4

f(3/4) = 25

Answer:

nine hundred  sixty

nine thousandths

Step-by-step explanation:

Answer:

b .

x = 3

y = 3[tex]\sqrt3[/tex]

Step-by-step explanation:

Using the pythagorean identities for 30-60-90° triangle,

we know the ratio of the sides is    x - x√3 - 2x

Since 2x = 6

Then smallest side is x (opposite ∠30°) = 6/2 = 3

The other side y , opposite ∠60° will be x√3 or 3√3.

9514 1404 393

Answer:

  B. x = 3; y = 3√3

Step-by-step explanation:

You only need to use your sense of triangles to choose the correct answer:

  x < y < 6

This relation fits only one answer choice:

  x = 3, y = 3√3

_____

Additional comment

For multiple choice questions, it isn't always about working the problem. Usually, it is about knowing what the answer has to look like. The usual criteria are (a) is the answer true; (b) does the answer make sense in the context of the problem statement; (c) can you get this answer if you work the problem in detail. More often than not, the first two criteria will let you choose the correct answer without doing any detailed solving.

Answer:

0.9545

Step-by-step explanation:

Given that :

Mean = 300

Standard deviation, σ = 18

Sample size, n = 144

Zscore = (x - mean) ÷ σ/√n

At score, x = 297

Zscore = (297 - 300) / (18/12) = - 2

P(Z< - 2) = 0.02275

At score, x = 303

Zscore = (303 - 300) / (18/12) = 2

P(Z< 2) = 0.97725

P(Z < 2) - P(Z < - 2) = 0.97725 - 0.02275 = 0.9545

The probability that the sample mean will be between 297 to 303 is 0.9545.

We have given that ,A population has a mean of 300 and a standard deviation of 18. A sample of 144 observations will be taken.

Mean = 300

Standard deviation, σ = 18

Sample size, n = 144

We have to find the probability that the sample mean will be between 297 to 303

Therefore we use the formula of Z score.

[tex]Zscore = \frac{ (x - mean)}{\sigma/\sqrt n}[/tex]

At the score, x = 297

Zscore = (297 - 300) / (18/12) = - 2

P(Z< - 2) = 0.02275

At score, x = 303

Zscore = (303 - 300) / (18/12) = 2

P(Z< 2) = 0.97725

Therefore we get,

P(Z < 2) - P(Z < - 2) = 0.97725 - 0.02275 = 0.9545

Therefore,the probability that the sample mean will be between 297 to 303 is 0.9545.

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Answer:

d 12

Step-by-step explanation:

27-3=24÷3=12 do the mathssssss

Answer:

If it was 11, it would be 33 dollars which is over the total so its not a.

It can't be b because that would be 27, and that would be on just notebooks not magazine

24 is correct because he baught one magazine so + 3 which is the total so it is C

Step-by-step explanation:

Answer:

[tex]\frac{2}{10}, 0.3, \frac{5}{10},0.8,\frac{9}{10}[/tex]

Step-by-step explanation:

Given

[tex]\frac{9}{10}, 0.3, 0.8,\frac{5}{10}, \frac{2}{10}[/tex]

Required

Order from the least

We have:

[tex]\frac{9}{10}, 0.3, 0.8,\frac{5}{10}, \frac{2}{10}[/tex]

Express all as decimal

[tex]0.9, 0.3, 0.8,0.50, 0.20[/tex]

Rearrange from least

[tex]0.20, 0.3, 0.50,0.8,0.9[/tex]

Express converted numbers as fractions

[tex]\frac{2}{10}, 0.3, \frac{5}{10},0.8,\frac{9}{10}[/tex]

Answer: 12

Step-by-step explanation:

Answer:

12

Step-by-step explanation:

Check the picture below

Answer:

2 over 5

Step-by-step explanation:

This means out of 5 students only three did their work so 5-3=2

And the number of students who did their work over the total number of students in the class to find the probability

The probability that none of them have done their homework is 0.57%

Probability refers to a possibility that deals with the occurrence of random events.

The probability of all the events occurring need to be 1.

We are given that there are 3 students who have done their homework.

If the teacher 2 chooses 2 students, then;

Total no. of Outcomes= 5

Students who did their homework = 3

Students who didn't do their homework is 5-3 = 2

Probability of no. of students who haven't done their homework.

P(e)= 2/5

Thus P(students who haven't done homework) P(e)=0.57%

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Answer:

I think the answer is 1/3

Step-by-step explanation:

1/6+1/6

=2/6=1/3

Answer:

1/3

Step-by-step explanation:

The possible outcomes are 1,2,3,4,5,6

The good outcomes are 3 and 5 = 2 good outcomes

P(3 or 5) = number of good outcomes / total outcomes

              = 2/6 = 1/3

Answer:

[tex](a)\ T_{a,b} =(x +a,y+b)[/tex]

[tex](b)\ F_{y\ axis} = (-x,y)[/tex]

[tex](c)\ F_{x\ axis} = (x,-y)[/tex]

[tex](d)\ R_{o,90^o} = (-y,x)[/tex]

[tex](e)\ R_{o,180^o} = (-x,-y)[/tex]

[tex](f)\ R_{o,270^o} = (y,-x)[/tex]

Step-by-step explanation:

Solving (a): Translate a units right, b units up

When a function is translated a units right, the number of units will be added to the x coordinate

When a function is translated b units up, the number of units will be added to the y coordinate.

So, we have:

[tex]T_{a,b} =(x +a,y+b)[/tex]

Solving (b): Reflect across y-axis

When a function is translated across the y-axis, the x coordinate gets negated.

So, we have:

[tex]F_{y\ axis} = (-x,y)[/tex]

Solving (c): Reflect across x-axis

When a function is translated across the x-axis, the y coordinate gets negated.

So, we have:

[tex]F_{x\ axis} = (x,-y)[/tex]

Solving (d): 90 degrees rotation counterclockwise

When a function is rotated 90 degrees counterclockwise, the y-coordinates gets negated and then swapped with the x-coordinate.

So, we have:

[tex]R_{o,90^o} = (-y,x)[/tex]

Solving (e): 180 degrees rotation counterclockwise

When a function is rotated 180 degrees counterclockwise, the coordinates are negated.

So, we have:

[tex]R_{o,180^o} = (-x,-y)[/tex]

Solving (f): 270 degrees rotation counterclockwise

When a function is rotated 270 degrees counterclockwise, the x-coordinates gets negated and then swapped with the y-coordinate.

So, we have:

[tex]R_{o,270^o} = (y,-x)[/tex]

Answer:

[tex]\sum_{n = 1} 2*(-5)^{n-1}[/tex]

Step-by-step explanation:

An arithmetic sequence is of the form:

[tex]A_n = A_{n-1} + d[/tex]

While a geometric sequence is of the form:

[tex]A_n = A_{n-1}*r[/tex]

notice that first, we have a change of sign in our sequence, so we already can discard the arithmetic sequence.

In fact, the pattern is kinda easy to see.

The first term is:

A₁ = 2

the second term is:

A₂ = -10

notice that:

A₂/A₍ = r = -10/2 = -5

The third term is:

A₃ = 50

the quotient between the third term and the second term is:

A₃/A₂ = 50/-10 = -5

Whit this we can already conclude that the n-th term of our sequence will be:

[tex]A_n = A_{n-1}*(-5)[/tex]

Then the summation will be something like:

[tex]\sum_{n = 1} A_n = A_1 + A_2 + A_3 + ... = 2 - 10 + 50 - ...[/tex]

We can write:

[tex]A_n = A_{n-1}*(-5) = (A_{n-2}*(-5))*(-5)) = A_1*(-5)^{n-1} = 2*(-5)^{n-1}[/tex]

Then the summation is just:

[tex]\sum_{n = 1} 2*(-5)^{n-1}[/tex]

Answer:

The mean of the data is 21.41

Step-by-step explanation:

To find the mean of a data set you must...

Add up all data values to get the sum

Count the number of values in your data set

Divide the sum by the count

The mean of the data set 21.8, 23.3, 18.9, 22.9, 19.4, 23.7, 21.8, 22.8, 20.9, 21.1, 21.5, 22.9, 18.8, 22.6, 22.3, 20.8, 20.3, 19.1, 23.3, 18.8, 19.8, 24.2 is 21.41 the asnwer is 21.41.

It is defined as the single number that represents the mean value for the given set of data or the closed value for each entry given in the set of data.

We have a data set:

{21.8, 23.3, 18.9, 22.9, 19.4, 23.7, 21.8, 22.8, 20.9, 21.1, 21.5, 22.9, 18.8, 22.6, 22.3, 20.8, 20.3, 19.1, 23.3, 18.8, 19.8, 24.2}

As we know from the definition of the mean:

The mean can be calculated using the formula:

Mean = sum of the data set/number of the data in the data set

Mean = 471/22

Mean = 21.409  ≈ 21.41

Thus, the mean of the data set 21.8, 23.3, 18.9, 22.9, 19.4, 23.7, 21.8, 22.8, 20.9, 21.1, 21.5, 22.9, 18.8, 22.6, 22.3, 20.8, 20.3, 19.1, 23.3, 18.8, 19.8, 24.2 is 21.41 the asnwer is 21.41.

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Answer:

16

Step-by-step explanation:

Set up the equation ->

x+32=3x  

(you can get this easily by writing the equation down as you read the problem)

--> revisiting  x+32=3x

-x on both sides to isolate the number and put the like terms together

We are left with  32=2x

Divide 2 on both sides, and you will get x (his current age) --> x=16

Roger is currently 16 years old.

Answer:

16

Step-by-step explanation:

3x = 32 + x

2x = 32

x = 16

Answer:

243840000 people

Step-by-step explanation:

The total sample size = 1000

Samole proportion of those who wear corrective lenses :

p = x / n ; n = sample size

p = 762 / 1000 = 0.762

To predict the number of people who wear corrective lenses :

Total population * p

320,000,000 * 0.762

= 243840000 people

Answer:

243840000

Step-by-step explanation:

Answer:

1. 0.0910 = 9.10% probability that exactly 180 passengers show up for the flight.

2. 0.4522 = 45.22% probability that at most 180 passengers show up for the flight.

3. 0.5478 = 54.78% probability that more than 180 passengers show up for the flight.

Step-by-step explanation:

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

And p is the probability of X happening.

Can be approximated to a normal distribution, using the expected value and the standard deviation.

The expected value of the binomial distribution is:

[tex]E(X) = np[/tex]

The standard deviation of the binomial distribution is:

[tex]\sqrt{V(X)} = \sqrt{np(1-p)}[/tex]

Normal probability distribution

Problems of normally distributed distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

When we are approximating a binomial distribution to a normal one, we have that [tex]\mu = E(X)[/tex], [tex]\sigma = \sqrt{V(X)}[/tex].

Assume that there is a 0.905 probability that a passenger with a ticket will show up for the  flight.

This means that [tex]p = 0.905[/tex]

Also assume that the airline sells 200 tickets

This means that [tex]n = 200[/tex]

Question 1:

Exactly, so we can use the P(X = x) formula, to find P(X = 180).

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 180) = C_{200,180}.(0.905)^{180}.(0.095)^{20} = 0.0910[/tex]

0.0910 = 9.10% probability that exactly 180 passengers show up for the flight.

2. When 200 tickets are sold, calculate the probability that at most 180 passengers show up for the flight.

Now we have to use the approximation.

Mean and standard deviation:

[tex]\mu = E(X) = np = 200*0.905 = 181[/tex]

[tex]\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{200*0.905*0.095} = 4.15[/tex]

Using continuity correction, this is [tex]P(X \leq 180 + 0.5) = P(X \leq 180.5)[/tex], which is the p-value of Z when X = 180.5. Thus

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{180.5 - 181}{4.15}[/tex]

[tex]Z = -0.12[/tex]

[tex]Z = -0.12[/tex] has a p-value of 0.4522.

0.4522 = 45.22% probability that at most 180 passengers show up for the flight.

3. When 200 tickets are sold, calculate the probability that more than 180 passengers show up for the flight.

Complementary event with at most 180 passengers showing up, which means that the sum of these probabilities is 1. So

[tex]p + 0.4522 = 1[/tex]

[tex]p = 1 - 0.4522 = 0.5478[/tex]

0.5478 = 54.78% probability that more than 180 passengers show up for the flight.

Answer:

see explanation

Step-by-step explanation:

The equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

Calculate m using the slope formula

m = [tex]\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]

with (x₁, y₁ ) = (0, - 3) and (x₂, y₂ ) = (4, 2) ← 2 points on the line

m = [tex]\frac{2-(-3)}{4-0}[/tex] = [tex]\frac{2+3}{4}[/tex] = [tex]\frac{5}{4}[/tex]

The line crosses the y- axis at (0, - 3 ) ⇒ c = - 3

y = [tex]\frac{5}{4}[/tex] - 3 ← equation of line

see the picture attached

Let x and y be the amounts (in mL) of the 4% and 15% solutions, respectively, that the scientist needs to use.

He wants to end up with a 44 mL solution, so

x + y = 44 mL

Each milliliter of 4% solution contains 0.04 mL of acid, while each mL of 15% contains 0.15 mL of acid. The resulting solution should have a concentration of 12%, so that each mL of it contains 0.12 mL of acid. Then the solution will contain

0.04x + 0.15y = 0.12 × (44 mL) = 5.28 mL

of acid.

Solve for x and y. In the first equation, we have y = 44 mL - x, and substituting into the second equation gives

0.04x + 0.15 (44 mL - x) = 5.28 mL

0.04x + 6.6 mL - 0.15x = 5.28 mL

1.32 mL = 0.19x

x ≈ 6.95 mL

==>   y ≈ 37.05 mL